microbiology with diseases by taxonomy 5th edition test bank

Microbiology with Diseases by Taxonomy Chapter 6 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 6 Answers 1CM
The concept map that describes culture media is shown below:

Microbiology with Diseases by Taxonomy Chapter 6 Answers 1CT
The characteristics of an organism are given by a scientist as:

• Chemoheterotrophic:
  A chemoheterotroph is an organism, which uses organic compounds as its source of carbon and source of energy.
• Aerotolerant:
  Aerotolerant organisms are those organisms, which prefer an atmosphere without oxygen. Since they are aerotolerant, these organisms can tolerate low levels of oxygen.
• Mesophilic:
  A mesophilic organism is one which can grow best in a temperature range of 20⁰C to 40⁰C.
• Facultatively halophilic bacillus:
  A facultatively halophilic organism is one which can tolerate high concentrations of salt. The cell membranes of such organisms are resistant to salt. It can also survive in normal conditions.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 1FB
Sources of carbon in different organisms are given below:

1. In photoautotrophs – carbon dioxide.
2. In chemoautotrophs – carbon dioxide.
3. In photoheterotrophs – organic compounds.
4. In chemoheterotrophs – organic compounds.

Sources of energy in different organisms are given below:

1. In photoautotrophs – light.
2. In chemoautotrophs – organic molecules.
3. In photoheterotrophs – light.
4. In chemoheterotrophs – organic compounds.

Sources of electrons in different organisms are given below:

1. In organotrophs – organic molecules.
2. In lithotrophs – inorganic sources.
3. In photoheterotrophs – organic molecules.
4. In photoautotrophs – organic molecules.
5. In chemoautotrophs – organic molecules.

Thus, sources of carbon, energy, and electrons are needed by all cells.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 1L
The labeled thioglycollate tubes are shown below:

1. Obligate aerobes are those organisms, which cannot live in the absence of oxygen.
2. Obligate anaerobes are those organisms that cannot live in oxygen, since oxygen is toxic to such organisms. These organisms in the electron transport chain cannot use oxygen as terminal electron acceptor.
3. Facultative anaerobes are those organisms, which can live in absence and presence of oxygen. These organisms can switch between aerobic respiration and fermentation.
4. Aero tolerant anaerobes are those organisms, which can tolerate low levels of oxygen. These organisms prefer anaerobic conditions to aerobic conditions.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 1MC
(a) An anaerobe:
An anaerobe cannot grow on a Petri plate. An anaerobe can grow only under specially maintained conditions. Oxygen should not be present for the growth of an anaerobe. In a Petri plate, aerobes usually grow. Viruses cannot grow on agar in a Petri plate. Hence, the option (a) is incorrect.
(b) Viruses on an agar surface:
Viruses cannot grow on agar surfaces in Petri plates. Viruses can grow only on specialized growth medium. They can also be grown in tissues like the egg. Viruses can grow on monolayers of bacterial cells. A colony of agar surface can grow in a Petri plate, in a lab. Hence, the option (c) is incorrect
(c) Barophiles:
Barophiles cannot grow on agar in a Petri plate. Barophiles are organisms, which live in areas of high pressures. Such pressures cannot be maintained in a laboratory; hence, cannot grow in a Petri plate. Organisms like viruses cannot grow on agar in the lab. Hence, the option (d) is incorrect
(d) A colony on an agar surface:
A colony on an agar surface can grow in a Petri plate in a lab. A colony usually means a bacterial or fungal colony. Only aerobes can grow in Petri plates. The growth of anaerobes can be seen only in special jars like the Gas Pak jar. Barophiles cannot grow on culture. Thus, a colony on an agar surface can grow on a Petri plate in the laboratory.
Hence, the correct option is (b) a colony on an agar surface.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 1SA
High temperature affects the life of a microbe:
Explanation
Condition of high temperature conditions affects the shape of molecules in a cell. When a cell is subjected to high temperatures many changes occur, unless it is a thermophile. In normal cells, the high temperature denatures the enzymes present in the cell. Moreover, the enzymes are deactivated and denatured. Denaturation is the process in which the shape of the enzyme is changed. The native conformation of an enzyme is important in the function of the enzyme.
Additionally, if conformation of the enzyme is destroyed, the function of the enzyme is lost. Due to the changes in the enzyme, the reactions taking part in the cell do not occur. In contrast, as a result of exposure to high temperatures, metabolism stops. Unless, the conditions are altered quickly, the cell will die.
Thus, the life of a microbe can change drastically if enzymes are denatured. Since, reactions are dependent on enzymes metabolism of a cell is also dependent on enzymes. When metabolism stops, the cell cannot continue its life processes.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 2CT
Heat of pasteurization kills microorganism:
Explanation
The process of pasteurization uses a temperature of 72⁰C to remove the pathogens in food. At a high temperature of 72⁰C, the enzymes of most of the pathogens become deactivated. When enzymes are deactivated or denatured, the metabolism of the cell grinds to a halt.
Additionally, organisms are usually divided into psychrophiles, mesophiles, and thermophiles.

1. Psychrophiles are the organisms, which prefer low temperatures close to freezing.
2. Mesophiles are those organisms, which prefer a medium range of 20⁰C to 40⁰C.
3. Thermophiles are those organisms, which can withstand high temperatures.

Since, the temperature used in pasteurization is, only thermophiles can withstand this process. The other organisms present are killed due to effect on enzymes and cellular metabolism.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 2FB
Singlet oxygen:
Explanation
Singlet oxygen acts as a reactive oxidizing agent and is very toxic. The singlet oxygen species are produced by the reaction of oxygen and light. Singlet oxygen species are removed by carotenoids in phototrophic microorganisms.
In humans, phagocytic cells use the singlet oxygen species to destroy pathogens that enter the body. After its use by phagocytic cells, the singlet oxygen species is removed from the cell. Humans have enzymes to remove toxic oxygen species from the body.
Singlet oxygen species is used in photodynamic therapy. In this therapy, the reactive oxygen species are used to kill cancer cells.
Singlet oxygen is a toxic form of oxygen. It is molecular oxygen in a higher energy state.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 2MC
(a) Obligate aerobe:
The term of obligate anaerobe describes an organism that cannot exist in the presence of oxygen. Obligate aerobes are those organisms, which cannot live in the absence of oxygen. They need oxygen compulsorily. An organism that cannot exist in the presence of oxygen would be an obligate anaerobe. Hence, option (a) is incorrect.
(b) Facultative aerobe:
Facultative aerobes are the organisms, which can live in the absence and presence of oxygen. These organisms can change between aerobic respiration and fermentation. An organism that cannot exist in the presence of oxygen would be an obligate anaerobe. Hence, option (b) is incorrect.
(c) Facultative anaerobe:
Facultative anaerobes are the organisms that can live either in absence or presence of oxygen. These organisms can switch between aerobic respiration and fermentation. An organism that cannot exist in the presence of oxygen would be an obligate anaerobe. Hence, option (d) is incorrect.
(d) Obligate anaerobe:
Obligate anaerobes are those organisms that cannot live in the presence of oxygen. Oxygen is toxic to such organisms. These organisms cannot use oxygen as the terminal electron acceptor in the electron transport chain.
Hence, the correct option is (c) obligate anaerobe.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 2SA
Microbes cannot tolerate low pH in human stomach:
Explanation
The above statement is supported by many scientists conducted in the research. The stomach is an organ, which has a low pH of 1.5. The low pH is maintained by the presence of HCl. Most of the microbes, which enter the digestive tract, are killed at low pH.
However, the acidic conditions of the stomach disrupt the cell membrane of the microbes. The cell membranes of most microbes are sensitive to the conditions present in the human stomach.
Additionally, few organisms are resistant to the acidic conditions of the stomach. One of them is the bacterium Helicobacter pylori. The organism causes the formation of peptic ulcers in the stomach wall. The ulcers are formed by combined action of stomach acid and bacterial action.
Thus, the statement “Microbes cannot tolerate low pH in the human stomach” is true.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 3CT
Differences between the dry weights of facultative anaerobe structures:
Explanation
When two cultures of a facultative anaerobe are grown under different conditions, they show differences in dry weights. When one culture is grown in the presence of oxygen and the other is grown in the absence of oxygen, difference in growth is observed.
In contrast, the organism is a facultative anaerobe that can grow in the presence or absence of oxygen. Moreover, it grows better in the presence of oxygen, since aerobic respiration gives higher energy yield when compared to anaerobic respiration.
Similarly, the culture in the presence of oxygen grows faster and has a high rate of metabolism. The culture in the absence of oxygen also grows, but does not have similar growth, rate as the other culture.
Thus, when the cultures are dried and weights are taken, the culture grown in the presence of oxygen show higher dry weight than the other culture.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 3FB
All amino acids possess the element of nitrogen. The basic structure of an amino acid is:

The nucleotides present in the nucleic acids contain the essential element of nitrogen. The basic structure of a nucleotide is given below:

The structures of the five nucleotides are:

Thus, the essential element of nitrogen is recycled from amino acids and nucleotides in all cells.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 3MC
(a) Causes hydrogen peroxide to become toxic:
The enzyme superoxide dismutase does not cause hydrogen peroxide to become toxic. Instead the enzyme detoxifies the toxic substance. The presence of hydrogen peroxide causes damage to cells. The enzyme detoxifies these radicals, so that the cells are not damaged. Hence, the option (a) is incorrect.
(b) The enzyme cannot neutralize singlet oxygen species in the cell. Singlet oxygen species are removed by carotenoids in phototrophic microorganisms. The enzyme superoxide dismutase detoxifies the toxic superoxide radicals generated by the processes of the cell. Hence, the option (c) is incorrect.
(c) The enzyme superoxide dismutase must be produced in aerobic organisms. The superoxide radicals are formed during electron transport and need to be removed from the cell. When these radicals are formed, they cause death of the cell. Anaerobic organisms do not have this enzyme; hence, cannot live in the presence of oxygen. Hence, the option (d) is incorrect.
(d) Superoxide dismutase detoxifies superoxide radicals. The enzyme detoxifies toxic superoxide radicals generated by the processes of the cell. The presence of hydrogen peroxide causes damage to cells. The enzyme detoxifies the radicals, so that the cells are not damaged.
Hence, the correct option is (b) detoxifies superoxide radicals.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 3SA
Relation of Quorum sensing in biofilm formation:
Explanation
The ability to respond changes in a density of population is called quorum sensing. In this process, bacteria respond to changes by using signal and receptor molecules. The process is often seen in biofilms where many species are present together.
Quorum sensing is important in the formation of biofilms. Biofilms are complex relationships among different organisms. The biofilms are found attached to surfaces like the surface of teeth. Additionally, biofilms develop an extracellular matrix, which is composed of DNA, proteins, and polysaccharides of cells. The extracellular matrix is responsible for attachment of cells to one another. It is also responsible in sticking of biofilm to its substrate.
Furthermore, the cells in the biofilm secrete molecules, which act as signals. Other cells have receptors for these signals. When the number of microbes increase, the concentration of the signal molecules also increase. The binding of the signals to receptors reach a certain threshold in the genes where expression gets suppressed.
Thus, the genes that are suppressed are then expressed and allow the biofilm to have new characteristics. Moreover, gives organisms the ability to form biofilms.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 4CT
Requirement of riboflavin to synthesize FAD:
Explanation
The nutritional requirement of some organisms includes vitamin riboflavin. This vitamin is used to synthesize the co-factor FAD. The cofactor FAD is used for many purposes in the cell. Moreover, FAD (oxidized flavin adenine dinucleotide) can change to FADH₂ (reduced flavin adenine dinucleotide) by accepting two protons.
The conversion is shown in the below structure:

In eukaryotes, the main role of FAD is an electron carrier in the electron transport chain. The number of ATP (adenosine triphosphate) molecules obtained from the oxidation of each molecule of FADH₂ is 2.
Thus, in the process of ??oxidation, FAD behaves as a coenzyme to the enzyme acyl coA dehydrogenase.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 4FB
Most of the organisms cannot synthesize some substances that are necessary for metabolism. The organic chemical substances are known as growth factors. For instance, some of the growth factors are listed below:

1. Vitamins.
2. Heme.
3. NADH.
4. Specific amino acids.

Vitamins may not be a growth factor for all organisms. In humans, many vitamins are growth factors. But in organisms like E. coli, can synthesize its own vitamins, they are not growth factors. Other nutrients, which are synthesized in humans, may be growth factors for E. coli. The growth factors can be used as coenzymes or as a part of molecules like cytochromes.
Thus, small organic molecules, which are required in low amounts for metabolism, are growth factors.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 4MC
(a) The peroxide anion:
Peroxide anions are present in hydrogen peroxide. The anion makes hydrogen peroxide an antimicrobial agent. The peroxide anion is detoxified by the enzymes catalase and peroxidase. The enzyme catalase converts the toxic hydrogen peroxide to water and oxygen. The most reactive of the four toxic forms of oxygen is the hydroxyl radical. Hence, the option (b) is incorrect.
(b) The superoxide radical:
The superoxide radicals are formed during electron transport and need to be removed from the cell. When these radicals are formed, they cause the death of the cell. Hydroxyl radical is the most reactive of the four toxic forms of oxygen. Hence, the option (c) is incorrect.
(c) Singlet oxygen:
The oxygen species are produced by reaction of oxygen and light. Singlet oxygen species are removed by carotenoids in phototrophic microorganisms. Singlet oxygen species is molecular oxygen with a higher energy state. The most reactive of the four toxic forms of oxygen is the hydroxyl radical. Hence, the option (d) is incorrect.
(d) The hydroxyl radical:
The radicals result from incomplete reduction of hydrogen peroxide. They can also result from ionizing radiation. These radicals are the most reactive of the four toxic forms of oxygen. In anaerobes, the radicals cause damage. In aerobes, no danger exists due to these radicals due to the presence of enzymes like catalase and peroxidase. Thus, hydroxyl radical is the most reactive form of oxygen.
Hence, the correct option is (a) the hydroxyl radical.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 4SA
Sterilization of instruments and vessels is important in microbiological procedures:
Explanation
The media, vessels, and instruments used in microbiology must be sterilized before use. The process of sterilization is very important in the field of microbiology. Sterilization is the process where all microbes are killed and destroyed.
The media used, for the growth of microbes must be sterilized. Media is usually sterilized in an autoclave. The temperature is 121⁰C for 15 minutes. The broth and agar must be sterilized before use to prevent the growth of any contaminants.
The vessels used are mainly glassware. These are washed, wrapped, and then placed in a hot air oven for sterilization. The temperature is 350⁰C for 2-3 hours.
The instruments used are the laminar air flow chamber and inoculation loops. The laminar air flow chamber is sterilized using UV light. The instruments to be used are placed inside the chamber. Inoculation loops and glass spreaders are kept inside the chamber and are sterilized.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 5CT
Oxygen requirement to bacteria:
Explanation
A bacterium is inoculated into a slant tube containing a complex medium. After incubation, only few colonies are seen on the surface of the agar. But many colonies are seen in the depth of the agar. Moreover, the slant of the agar shows few colonies, while butt shows prolific growth. The oxygen requirements of the bacterium can be determined by observing the growth in the tube.
Since, few colonies are seen on the surface of the agar and many colonies in the depth of the agar, it indicates that the bacterium is an aerotolerant anaerobe. Aerotolerant anaerobes are those organisms, which prefer an anaerobic environment. They grow best under anaerobic conditions, but can tolerate oxygen.
Thus, the prolific number of colonies inside the agar shows that the bacterium is an anaerobe. The scant colonies seen on the surface of the agar prove that the bacterium is an aerotolerant anaerobe.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 5FB
Each organism has a growth range to function properly. Within the growth range, three types of temperatures are facilitated, which are given below:

1. Optimum temperature.
2. Minimum growth temperature.
3. Maximum growth temperature.

The optimum temperature is the temperature at which the organism has the highest growth rate. All its systems are function properly and metabolism is at its highest range.
The lowest temperature where a microbe can metabolize is minimum growth temperature. Once the temperature goes lesser, minimum growth temperature prevails and cell membranes become less fluid. Moreover, transport processes are very slow to support metabolism.
The maximum growth temperature is the highest temperature at which a microbe can metabolize. Once the temperature goes higher the growth temperature is higher and the enzymes are denatured for vital processes.
The lowest temperature, microbe can metabolize at minimum growth temperature. Beyond the minimum growth temperature, metabolism does not occur, due to inactivation of necessary molecules.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 5MC
(a) Aerotolerant:
Aerotolerant microbes are the organism, which prefer an anaerobic atmosphere, but can tolerate low levels of oxygen. Microaerophiles that grow best with a low level of oxygen and a high concentration of carbon dioxide are called capnophiles. Hence, the option (a) is incorrect.
(b) Facultative anaerobes:
Facultative aerobes are the organisms, which can live in the absence and presence of oxygen. The organisms cannot exist in high concentrations of carbon dioxide and less concentration of oxygen. Capnophiles are organisms, which can exist in low levels of oxygen and high concentrations of carbon dioxide. Hence, the option (c) is incorrect.
(c) Fastidious:
A fastidious organism has complex requirements for its growth. It can grow only when specific nutrients are added. The organisms cannot grow at low concentrations of oxygen and high concentrations of carbon dioxide. Capnophiles are organisms which can exist at low levels of oxygen and high concentrations of carbon dioxide. Hence, the option (c) is incorrect.
(e) Capnophiles:
Microaerophiles that grow best with a low level of oxygen and a high concentration of carbon dioxide are called capnophiles. Capnophiles are organisms, which can exist in low oxygen levels and high concentrations of carbon dioxide. The organisms are microaerophiles with slightly different requirements.
Hence, the correct option is (b) capnophiles.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 5SA
Agar is used in microbiology as a solidifying agent. Media without the addition of agar is known as broth, which is liquid in consistency. When agar is added, the medium becomes solid.
Agar is a polysaccharide, which is complex in nature and derived from the cell walls of certain red algae.
Agar is very useful in the field of microbiology because of the following reasons:

• Agar cannot be digested by most microbes. Hence, even with the growth of microbes and fungi, the media stays solid.
• Agar comes in powder form, which can dissolve in water at. At this temperature, most of the added nutrients remain unchanged and undamaged.
• The solidification of agar is seen at temperatures below. This temperature allows us to add nutrients like blood without any problem.
• The agar at such temperatures can also be poured over bacterial culture without any problem. This is seen in the pour plate technique.
• Once agar becomes solidified, it does not melt unless heated to temperatures above. This characteristic of agar can be used while growing thermophiles.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 6CT
Nutritional and oxygen characteristics of bacteria in everyday language:
Explanation
An article gives the following characteristics of a bacterium:

• Obligate microaerophilic.
• Chemoorganoheterotroph.

An obligate microaerophilic is an organism, which need to have a concentration of 2%-10% of oxygen in the air. Higher concentrations of oxygen cannot be tolerated by the bacterium. Since, it is an obligate it indicates the absence of the oxygen concentration, the bacterium cannot survive.
Additionally, chemoorganoheterotroph is an organism, which uses organic compounds as its source of carbon. It obtains its energy from redox reactions in organic compounds. Redox reactions are reduction and oxidation reactions.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 6FB
Osmotic pressure is responsible for shrinking of cells seen in hypertonic solutions like saltwater.
Solutions can usually be described in three ways:

• Hypertonic
• Isotonic
• Hypotonic

Hypertonic solutions have higher concentration of solutes compared to the cell. The water from the cell moves out into the surrounding solution and the cell shrivels.
Isotonic solutions have the same concentration of solutes as the cell. In this situation, the cell does not undergo any change.
Hypotonic solutions have lower concentration of solutes compared to the cell. The water from the solution moves into the cell and it bursts.
Saltwater is a hypertonic solution which results in the shrinking of cells seen. Thus, cells that shrink in hypertonic solutions such as saltwater are responding to osmotic pressure.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 6MC
(a) Cholesterol:
Some organisms might need cholesterol as a growth factor. Since, cholesterol is one of the molecules present in the cell membrane, some organisms require as a nutrient. Presence of cholesterol in the cell membrane prevents quick crystallization of the lipids in the membrane. Cholesterol helps to keep the fluidity of the membrane. Hence, the option (a) is incorrect.
(b) Vitamins:
Vitamins are one of the growth factors needed for many microorganisms. Vitamins are needed for many purposes in the cell. Since, many organisms cannot synthesize all the required, vitamins need them as a growth nutrient. Vitamins act as coenzymes in metabolism and are required in the cell. Hence, the option (c) is incorrect.
(c) Heme:
Heme is an important constituent required in a cell. The cytochromes, which take part in the electron transport chain, consist of heme. Without cytochromes, the process of aerobic respiration cannot occur. In photosynthetic organisms, photophosphorylation cannot take place in the absence of cytochromes. Hence, the option (d) is incorrect.
(d) Water:
Water is a constituent which is not required as a growth factor. Since, water can be obtained easily, it is not considered as a growth factor. Even if the cell does not take in water, the metabolic water obtained is usually enough for the needs of the cell. Hence, water need not be added as a nutrient for growth. Thus, water is not a required growth factor for various microbes.
Hence, the correct option is (b) water.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 6SA
The difference between complex media and defined media is that the exact composition of a complex medium is unknown while that of a defined medium is known.
In a defined medium, the exact chemical composition of the medium is known. Every ingredient is known and the exact amount of each ingredient is known. Some media can support the growth of many organisms. But some media are specific for the growth of some microbes only.
In a complex medium, partially digested yeast, beef extract, and casein are added. The exact composition of the medium is not known since the process of partial digestion releases different chemicals in different concentrations.
A complex medium can support the growth of many microbes. They can be used to culture microbes whose nutritional requirements are not fully known.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 7CT
The elements of phosphorous, sulfur, iron, and magnesium are required by microorganisms. These elements are used in the following way:
Phosphorous:
The phosphate ion is present in the phosphodiester linkages of DNA. The addition of a phosphate ion can activate or deactivate a molecule in the process of signal transduction.
Sulfur:
Sulfur containing compounds act as electron donors and electron acceptors. Sulfur is also present in many enzymes. Two amino acids possess the element of sulfur. Sulfur is a vital part of disulfide bonds.
Iron:
The molecules of hemoglobin and myoglobin contain the element of iron. The active sites of many enzymes also contain the element of iron. The element is also a part of cytochromes, which are vital for the process of electron transport chain.
Magnesium:
Many enzymes need magnesium ions to function properly. It plays a vital role in the manipulation of compounds like ATP, DNA, and RNA. This ion has an important interaction with the phosphate present in nucleic acids.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 7FB
Obligate halophiles:
Explanation
Normal cells cannot exist in either hypotonic or hypertonic solutions. They can exist only in isotonic solutions.
The halophiles are the organisms, which have the ability to resist high osmotic pressures. They do not behave like other cells when placed in hypertonic solutions. The halophiles burst when placed in hypotonic solutions. Obligate halophiles are those organisms, which are adapted to such high osmotic conditions.
There are also organisms called facultative halophiles, which can tolerate high concentrations of salt. They do not require them, but can exist in them. These organisms can tolerate slightly lesser salt concentrations than obligate halophiles. Unlike other organisms, which shrivel in hypertonic solutions adjust to osmotic conditions.
Those organisms, which can exist in salty conditions, due to their ability to withstand high osmotic pressures are called as obligate halophiles.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 7MC
(a) Barophiles:
Barophiles are organisms, which live in areas of high pressures. The organisms are generally found at the bottom of oceans. These organisms cannot thrive in icy waters. Organisms, which are called psychrophiles, live in icy waters preferentially. Hence, the option (a) is incorrect.
(b) Thermophiles:
Thermophiles are those organisms, which can withstand high temperatures. The organisms are seen in places like hot springs and deep sea vents. The organisms cannot thrive in icy waters. Organisms, which are called psychrophiles, live in icy waters preferentially. Hence, the option (b) is incorrect.
(c) Mesophiles:
The organisms live at moderate temperatures. They cannot live in too cold or too hot temperatures. These organisms cannot thrive in icy waters. Organisms, which are called psychrophiles, live in icy waters preferentially. Hence, the option (c) is incorrect.
(d) Psychrophiles:
The organisms can live in icy cold waters. The organisms can be found in glaciers and ice caps. Moreover, the organisms have cell membranes, which can resistant to the extreme cold conditions. The DNA of the microbes can resist low temperatures. Thus, psychrophiles are the organisms, which can happily thrive in icy waters.
Hence, the correct option is (d) psychrophiles.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 7SA
The four distinct phases seen in a bacterial growth curve are shown in the graph below:

In the lag phase, the cells adjust to the new surroundings where they are inoculated. The cells synthesize enzymes needed for the latter phases. The length of the lag phase differs from species to species. It also depends on the nutrients present in the medium.
In the log phase, the number of cells increases rapidly and logarithmically. The synthesis of DNA (deoxyribonucleic acid) and proteins occur rapidly as new cells are formed. The metabolic rate is at a maximum during this phase.
In the stationary phase, the rate of reproduction decreases gradually. Slowly the number of cells synthesized equals the number of cells dying. The death of cells seen is due to accumulation of by-products. This phase is called stationary phase because the exponential growth slowly stops.
In the death phase, the nutrients are depleted and wastes accumulated. This results in death of the cells at a faster rate that the synthesis of cells. Sometimes all the cells in the culture die, while in some cultures a few cells remain alive. This phase is called death phase because most of the cells die.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 8FB
Carotenoids pigments:
Explanation
Singlet oxygen is molecular oxygen in toxic form with higher energy state. This species is very toxic. Singlet oxygen acts as a reactive oxidizing agent. Additionally, the singlet oxygen species are produced by the reaction of oxygen and light. They are produced during the process of photosynthesis in chlorophyll molecules.
In phototrophic organisms, carotenoid pigments remove toxic form of oxygen. The excess energy of this species is removed by carotenoids. Another method is quenching of the species.
The photochemically produced singlet oxygen in phototrophic organisms is removed from cells by the pigment called carotenoid.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 8MC
(a) Live at normal barometric pressure:
Barophiles do not live at normal barometric pressures. Barophiles are organisms, which live in areas of high pressures. The organisms are generally found at the bottom of oceans where the pressure is quite high. Hence, the option (b) is correct.
(b) Die if put under high pressure:
Barophiles do not die under high pressures. Barophiles live in areas of high pressures. The organisms have the capability to grow at high pressure in the bottom of oceans. Hence, the option (c) is correct.
(c) Thrive in warm air:
Barophiles cannot live in warm air. Their cells are tailored to withstand high pressure conditions. Barophiles are organisms, which live in areas of high pressures like deep sea vents and bottom of oceans. Hence, the option (d) is correct.
(d) Barophiles cannot infect and cause disease in humans. Barophiles are organisms, which live in areas of high pressures. These organisms are generally found at the bottom of oceans. Since, the pressure in human cells is not very high, these organisms cannot infect humans. Thus, barophiles cannot cause disease in humans. Hence, the option (a) is correct.
Hence, the correct option is (a) cannot cause disease in humans.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 8SA
The number of cells in 1 ?l of sewage is 47.
The number of cells estimated to be in 1 liter of sewage can be calculated as follows:
1 liter = 1000000 ?l
When 1 ?l contains 47 cells, 1 liter of sewage will contain:
= 47×1000000
= 47,000,000 cells
The number of cells in one liter of sewage would be 47,000,000 cells.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 9FB
Nitrogen fixation:
Explanation
Many cyanobacteria and Rhizobium species are vital in the process of nitrogen fixation. The atmospheric nitrogen is converted into ammonia. Nitrogen fixation can occur naturally and with the help of microbes. Naturally nitrogen fixation occurs by means of lightning.
Similarly, nitrogen fixation is usually carried out by Rhizobium species. An enzyme called nitrogenase is present in the bacteria. This enzyme works best under anaerobic conditions. The roots of plants like legumes contain nodules to harbor the bacteria.
The nodules provide bacteria an anaerobic environment to work and reduce nitrogen in exchange for protection. The anaerobic environment is obtained using the pigment leghemoglobin.
Nitrogen fixation is the process by which N₂(nitrogen) is converted to NH₃(ammonia) by microbes.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 9MC
(a) Broth culture:
A broth culture is one in which the medium is liquid in consistency. A loopful of culture is then mixed in the broth. The medium before inoculation is usually transparent. After incubating the broth for 24-48 hours, the broth becomes turbid, due to the growth of the microbes. Hence, the option (a) is incorrect.
(b) Pour plate:
A pour plate method is a technique in which the microbial culture is mixed in liquid agar. The agar is then poured into Petri plates and left to cool. In this method some sub-surface colonies are formed. Some colonies are formed inside the agar. This is not a technique for isolated colonies. Hence, the option (b) is incorrect.
(d) Dilution plate:
The technique of dilution plate is to use the process of serial dilution. The broth with culture is diluted serially and each dilution is then streaked on the agar plate. The difference in the number of colonies on the plates helps us to know the original number of microbes. Hence, the option (d) is incorrect.
(e) Streak plate:
The streak plate method is a laboratory technique in which a sterile inoculating loop of culture is moved across an agar plate to obtain isolated colonies. Moreover, in the technique a sterilized inoculating loop is used to spread a loopful of culture across the surface of an agar plate. The repeated moving of the loop across the plate in different directions allows the isolation of single colonies.
Hence, the correct option is (c) streak plate.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 9SA
The three indirect methods of counting microbes are:
Measurement of metabolic activity:
The rate of utilization of nutrients and the rate of production of waste is dependent on the number of cells in the culture. By taking these two factors into account, the rate of metabolism can be determined. When the rate of metabolism is known, the number of cells in the culture can be known.
Dry weight:
Some organisms, which have filaments, cannot be easily counted. In the case of such organisms, filtration is followed by drying of the cells. The dry cells are then weighed.
Turbidity:
Turbidity can be measured only in liquid culture. Turbidity can be measured using a spectrophotometer. This instrument measures the amount of light transmitted through the liquid. As bacterial growth makes the liquid turbid, more light is absorbed or scattered. Very less light is transmitted if growth of culture is seen.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 10FB
Streak plate method:
Explanation
The streak plate method is one of the laboratory techniques in which a researcher streaks a plate many times by flaming the loop. This method is used to get isolated colonies. A single loopful of culture is taken and streaked in one direction on the plate. After flaming the loop, the culture on the plate is again streaked in another direction.
Similarly, the action is repeated in many directions. The repeated moving of the loop across the plate in different directions allows isolation of single colonies.
Additionally, other laboratory technique are isolated and colonies are obtained is serial dilution. The technique of dilution plate is to use the process of serial dilution. The broth with culture is diluted serially and each dilution is streaked on an agar plate. Isolated colonies are obtained in the last few plates.
Thus, the streak plate method is used to isolate micro organisms.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 10MC
(a) Agar is available for microbial nutrition:
Agar is a constituent of most microbial media, but it does not give any nutrition to the microbe. Agar is meant as a solidifying agent. A defined medium is one in which the exact composition of the medium is known. Hence, the option (b) is incorrect.
(b) Blood may be included:
Blood can be included in some media like blood agar. It is needed for the microbes, which lyse the blood cells. But the presence of blood in a medium doesn’t make it a defined medium. A defined medium is one in which the exact composition of the medium is known. Hence, the option (c) is incorrect.
(c) Organic chemicals are excluded:
The medium in which organic chemicals are excluded is not a defined medium. Some organic chemicals are added in media. A defined medium is one in which the exact composition of the medium is known. Hence, the option (d) is incorrect.
(d) The particular medium containing the chemical composition is known:
A defined medium is one in which the exact composition of the medium is known. Every constituent in the medium is known and the exact amount of each ingredient is known. The particular medium containing the chemical composition is known as a defined medium.
Hence, the correct option is (a) the exact chemical composition of the medium is known.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 10SA
The five direct methods of counting microbes are:

• Serial dilution and viable plate counts:
  The process of serial dilution is usually used when the number of microbes is very high in a small sample. The sample is serially diluted. Each tube of the dilution is then plated and incubated. The colonies of the last dilutions can be easily counted. The number of microbes in the original sample can then be determined by multiplying the dilution factor with the number of colonies found on the plate.
• Membrane filtration:
  The process of membrane filtration is done by pouring a large sample of fluid through a membrane filter. The filter traps the cells in the liquid. The membrane is then transferred to a solid medium. The cells are then allowed to grow. The number of colonies indicates the number of organisms in the original sample.
• Most probable number:
  This is a statistical technique, which uses MPN (most probable number) tables. The sample is diluted in sets of tubes. Each dilution has five tubes. After incubation, the number of tubes in each dilution which shows turbidity is counted. This number is then compared with the numbers in the MPN table. The MPN table then gives the estimate of the number of bacteria in the sample.
• Microscopic counts:
  Counting chambers like the Petroff-Hausser counting chamber is used in this method. The microbiologist can count the number of cells in the grid. The number of cells can be used to determine the number of bacteria in 1 ml of the sample.
• Electronic counters:
  Electronic counters like the Coulter counter are used to count cells. Mainly large cells are counted using this method. An electric current is used in this counter. When cells interrupt the flow of the current, they are counted.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 11MC
(a) Logarithmic reproduction of the growth curve:
The best method to represent bacterial growth as a growth curve is to use a semilogarithmic graph. A logarithmic graph does not show the bacterial growth curve properly. So, it is not used for plotting bacterial growth. Hence, the option (a) is incorrect.
(b) An arithmetic graph of the lag phase followed by a logarithmic section for the log, stationary, and death phases:
By showing the lag phase in an arithmetic graph and the rest of the phases in a logarithmic graph, the exact growth curve is not obtained. It is also confusing when plotting on two graphs. A semilogarithmic graph is the best method to represent bacterial growth, as a growth curve. Hence, the option (c) is incorrect.
(c) None of the above would best represent a population growth curve:
A semilogarithmic graph is the best method to represent bacterial growth, as a growth curve. The four phases of bacterial growth can be easily seen when using a semilogarithmic graph. Hence, the option (d) is incorrect.
(d) A semilogarithmic graph using a log scale on the y axis:
A semilogarithmic graph is the best method to represent bacterial growth as a growth curve. Using a log scale on the y axis, when bacterial growth is plotted, four phases are seen. The four phases are – lag, log, stationary, and death phase. A semilogarithmic graph using a log scale on the y axis is the most useful, while showing population growth on a graph.
Hence, the correct option is (b) a semilogarithmic graph using a log scale on the y axis.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 11SA
The differences between the different groups are shown according to the source of carbon, energy, and electrons.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 12MC
(a) Dry weight:
When filamentous organisms are present, direct counting methods cannot be used. The filamentous organisms are filtered, dried, and weighed. The method is known as dry weight method and is an indirect method. It is not the best method for counting fecal bacteria in a stream. Hence, the option (a) is incorrect.
(b) Turbidity:
Turbidity can be measured in liquid culture. Turbidity can be measured using a spectrophotometer. The instrument measures the amount of light transmitted through the liquid. As bacterial growth makes the liquid turbid, more light is absorbed or scattered. Very less light is transmitted. It is not the best method for counting fecal bacteria in a stream. Hence, the option (b) is incorrect.
(c) Viable plate counts:
Viable plate counts can be done after the process of serial dilution. After the process of serial dilution, each dilution is then plated on an agar plate. After incubation, the cells are counted on a culture plate. The original number of microbes in the original sample can be determined by multiplying the number of cells into the dilution factor. It is not the best method for counting fecal bacteria in a stream. Hence, the option (c) is incorrect.
(d) Membrane filtration:
The process of membrane filtration is done by pouring a large sample of fluid through a membrane filter. The filter traps the cells in the liquid. The membrane is then transferred to a solid medium. The cells are then allowed to grow. The number of colonies indicates the number of organisms in the original sample. Thus, the best method for counting fecal bacteria in a stream to determine the portability of the water would be membrane filtration.
Hence, the correct option is (d) membrane filtration.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 12SA
The composition of the Escherichia coli medium is given below:

• Glucose – 1 g
• Na₂HPO₄ – 16.4 g
• KH₂PO₄ – 1.5 g
• (NH₄)₃PO₄– 2 g
• MgSO₄.7H₂O – 0.2 g
• CaCl₂ – 0.01 g
• FeSO₄.7H₂O -0.005 g
• Distilled water – bring volume to 1 liter

The compositions of the blood agar and MacConkey agar are shown below:
Blood agar:

• Agar – 15 g
• Pancreatic digest of casein – 15 g
• Papaic digest of soybean mean – 5 g
• NaCl – 5 g
• Sterile blood – 50 ml
• Distilled water – to bring volume to 950 ml

MacConkey agar:

• Peptone – 20 g
• Agar – 12 g
• Lactose – 10 g
• Bile salts – 5 g
• NaCl – 5 g
• Neutral red – 0.075 g
• Crystal violet – 0.001 g
• Distilled water – to bring volume to 1 liter

The E. coli medium is described as defined while blood agar and MacConkey agar are described as complex.
The E. coli medium is described as defined because all the components of the medium are known. The exact amount of each ingredient is also known. When all the components are known in a medium along with the amount of each ingredient, it is known as a defined medium.
The blood agar is described as a complex medium because of the presence of blood and other substances like casein, and soybean. The presence of digested proteins also makes the medium complex. A medium is defined as complex when the exact chemical composition is not known. Since partial digestion releases different chemicals in different concentrations, the exact chemical composition is not known.
The MacConkey agar is described as a complex medium because it is used as a differential medium to differentiate between coliforms and non-coliforms. This medium inhibits the growth of other organisms and only allows the growth of coliforms.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 13MC
(a) A statistical estimation using 15 dilution tubes and a table of numbers to estimate the number of bacteria per milliliter:
A Coulter counter is not a statistical estimation using tubes and a table of numbers. It is a device that directly counts microbes when they pass in front of an electronic detector. Hence, the option (a) is incorrect.
(b) An indirect method of counting microorganisms:
The indirect methods of counting microorganisms are dry weight, measurement of metabolic activity, turbidity, and analysis of kinds of genetic sequences. A Coulter counter is a device that directly counts microbes when they pass in front of an electronic detector. Hence, the option (b) is incorrect.
(c) A device that directly counts microbes that are differentially stained with fluorescent dyes:
The Coulter counter does not use fluorescent dyes, but electricity to detect the number of cells. It is a device that directly counts microbes when they pass in front of an electronic detector. The detector detects the number of times the flow of electric current is interrupted. It does not depend on the principle of fluorescence. Hence, the option (c) is incorrect.
(d) A device that directly counts microbes as they pass through a tube in front of an electronic detector:
The Coulter counter is a device that directly counts microbes when they pass in front of an electronic detector. The cells are counted when they interrupt the flow of electric current. This counter is mainly used for large cells like yeast, algae, and protozoa. A device that directly counts microbes when they pass in front of an electronic detector is known as a Coulter counter.
Hence, the correct option is (c) a device that directly counts microbes as they pass through a tube in front of an electronic detector.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 14MC
(a) Deep-freezing:
The process of deep-freezing is placing the culture at temperatures between -50⁰C to -95⁰C. When cultures are frozen using this method they need to be thawed and then placed in a suitable medium. Deep-freezing is not freeze-drying. The process of lyophilization is the removal of water molecules from a culture using a vacuum. Hence, the option (b) is incorrect.
(b) Refrigeration:
The process of refrigeration is the best technique for short-term storage of culture. Cultures stored in this way cannot be stored for many years. The process of refrigeration does not indicate the process of freeze-drying or lyophilization. The process of lyophilization is the removal of water molecules from a culture using a vacuum. Hence, the option (c) is incorrect.
(c) Pickling is the method in which cultures are preserved in brine solutions. This type of preservation is usually seen in food preservation. Pickling does not involve low temperatures at all. It is not the process of freeze-drying or lyophilization. The process of lyophilization is the removal of water molecules from a culture using a vacuum. Hence, the option (d) is incorrect.
(d) Freeze-drying is called as lyophilization. In the process of lyophilization the removal of water molecules from a culture is by using a vacuum. The culture needs to be frozen for this process. The ice in the culture directly undergoes the process of sublimation to become a gas. The culture does not sustain any damage of any sort and can be preserved for many years.
Hence, the correct option is (a) freeze-drying.

Microbiology with Diseases by Taxonomy Chapter 6 Answers 15MC
(a) A characteristic of most bacteria:
The process of quorum sensing is not present in most bacteria. The process of quorum sensing is the ability to react to variations in the density of a population. It is mainly seen in the organisms of a biofilm and helps the organisms to get new characteristics. Hence, the option (b) is incorrect.
(b) Dependent on direct contact among cells:
The process of quorum sensing is not dependent on direct contact among cells. It depends on the signals released by microbes. When many species of microbes are present in a biofilm, they secrete molecules into the matrix which act as signals. Direct contact among cells is not needed. Hence, the option (c) is incorrect.
(c) The process of quorum sensing is not associated with colonies present on an agar plate. The colonies on an agar plate mostly do not show the process of quorum sensing. It is mainly seen in the organisms of a biofilm and helps the organisms to get new characteristics. Hence, the option (d) is incorrect.
(d) The ability to alter the changes in the density of a population is quorum sensing. In this process, bacteria can respond to these changes by using signal and receptor molecules. This process is often seen in biofilms where many species are present together.
Hence, the correct option is (a) the ability to respond to changes in population density.

Microbiology with Diseases by Taxonomy Chapter 5 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 5 Answers 1CM
The terms given in the question are:

• 2 ATP (2)
• 34 ATP
• Chemiosmosis
• Electron transport chain
• Glycolysis
• Krebs cycle
• Oxidative phosphorylation
• Substrate level phosphorylation (2)
• Synthesis of acetyl coA

Glycolysis is the major metabolic pathway of the living organisms. Energy is produced in this pathway in the form of ATP (adenosine triphosphate). 2 ATPs are produced at the end of the glycolysis and the final product is pyruvate. The pyruvate then enters into the TCA (tricarboxylic cycle) or Krebs cycle by forming acetyl CoA. In TCA cycle reducing agents like NADH (Nicotinamide adenine dinucleotide) and FADH2 (flavin adenine dinucleotide) are produced. They are used in electron transport chain to synthesize ATP by oxidative phosphorylation.
The concept map which includes all the above terms and describes aerobic respiration is given below:

Microbiology with Diseases by Taxonomy Chapter 5 Answers 1CT
An organism that uses glycolysis and TCA (tricarboxylic acid) cycle or Kreb’s cycle might also need the pentose phosphate pathway.
The pentose phosphate pathway can be used for the reduction of coenzymes and for specific by-products, which are needed for anabolic pathways. These by-products are the precursors in anabolic reactions. The reduced coenzymes are also useful in anabolic reactions.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 1FB
Cyclic photophosphorylation:
Explanation:

1. In cyclic photophosphorylation, the electrons from the reaction center pass through electron transport chain and back to the reaction center.
2. The reaction center of chlorophyll is present in a photosystem. Light energy from the sun excites the electrons in the reaction center.
3. These electrons then pass on to an acceptor molecule. The electrons pass through an electron transport chain and back to the chlorophyll molecule.
4. In non-cyclic photophosphorylation, the electrons do not return to the place of origin.

The cyclic photophosphorylation process is shown in the diagram below:

Thus, the final electron acceptor in cyclic photophosphorylation is the original reaction center, chlorophyll.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 1M
Substrate-level phosphorylation:
Explanation
Substrate-level phosphorylation occurs when energy from a compound containing phosphate reacts with ADP (adenosine triphosphate) to form ATP (adenosine triphosphate). The direct transfer of a phosphate group between two substrates from ATP is known as substrate-level phosphorylation.
Similarly, the process of substrate-level phosphorylation can be seen in the glycolysis pathway. The formation of pyruvate in the last step of glycolysis is a substrate-level phosphorylation. The phosphate from phosphoenol pyruvate is transferred to an ADP molecule to form ATP.
Thus, substrate-level phosphorylation occurs in Krebs cycle of the mitochondria. This process is a fast source of ATP in the cell that is independent of respiration and external electron acceptors.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 1MC
Both anabolism and catabolism:
Anabolism is the synthesis of complex molecules or large molecules from simpler, smaller molecules. The process of catabolism is the breakdown of large molecules into smaller ones. In an amphibolic pathway, both these processes occur.
Hence, the option (b) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 1SA
Enzymes are necessary for anabolic reactions to occur in living organisms.
Anabolic reactions are those reactions in which the synthesis of complex and bigger molecules takes place. Most of the reactions cannot occur in the absence of the specific enzyme. Sometimes these enzymes act as catalysts.
A catalyst is a molecule, which reduces the activation energy of a reaction. Many reactions have high activation energy and cannot occur in the absence of a catalyst. The conditions of the cell are not suitable for the high activation energies of some reactions. When the activation energy is lowered, the reactions can easily occur in the cell.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 2CT
Bacterial fermentation causes milk to have a sour taste.
The fermentation of milk is done by bacteria, which change the lactose present in the milk to lactic acid. The lactic acid formed is responsible for the sour taste of the fermented milk.
Lactose is a disaccharide consisting of glucose and galactose. Both these sugars are broken down by the process of glycolysis. The product of glycolysis is pyruvic acid. This pyruvic acid is then converted to lactic acid by bacteria.
The bacteria which carry out fermentation are:

• Lactobacillus
• Lactococcus
• Leuconostoc

Microbiology with Diseases by Taxonomy Chapter 5 Answers 2FB
In the pathway of glycolysis, there is a preparatory phase and a pay-off phase. In the preparatory phase, 2 ATP molecules are used up. In the pay-off phase, 4 ATP molecules are generated. Thus a net gain of 2 ATP molecules is seen.
The pathway of glycolysis can occur in the anaerobic or the aerobic stages.
The pathway of glycolysis is shown below:

Microbiology with Diseases by Taxonomy Chapter 5 Answers 2M
Formation of ATP (adenosine triphosphate) involves formation of oxidative through reduction of coenzymes in the electron transport chain.
In the process of oxidative phosphorylation, the transfer of electrons occurs from electron donors to electron acceptors. This is mainly seen in the electron transport chain. When electrons are transferred, energy is produced. The energy is used in the transport of protons across the membrane. The transport of protons causes the formation of ATP.
This process produces superoxide and hydrogen peroxide, which can damage the cell. The process of oxidative phosphorylation is shown in the diagram:

Microbiology with Diseases by Taxonomy Chapter 5 Answers 2MC
Both anabolism and catabolism:
Anabolism is the synthesis of complex molecules or large molecules from simpler, smaller molecules. The process of catabolism is the breakdown of large molecules into smaller ones. In an amphibolic pathway, both these processes occur.
Hence, the option (b) is incorrect.
Catabolism only:
The process of catabolism is the breakdown of large molecules into smaller ones. A good example would be the process of glycogenolysis. In this process, the large molecule of glycogen is broken down into small molecules of glucose. Catabolism does not include synthesis reactions.
Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 2SA
Organisms can control the rate of metabolic activities in the cells by many ways.
One way is through enzymes. Enzymes are needed for almost every reaction, which proceeds in the cell. After the required reaction is complete, the cell destroys the enzyme or deactivates it. In this way, the enzyme cannot work unless activated or synthesized again.
Another method of control is by regulators. A good example would be the lac operon. In the lac operon, there are many genes, which are under the control of a single regulator gene. Only when the cell requires these enzymes, the genes are turned on. Otherwise they are turned off.
The cell also contains inhibitors, which are specific for some substrates. These bind to the enzymes and inhibit their action. In this way, the control of some reactions occurs.
Some other methods of control are:

• Changes in membrane potential
• Modifying substrates
• Phosphorylation

Microbiology with Diseases by Taxonomy Chapter 5 Answers 3CT
The protozoa Giardia intestinalis and Entamoeba histolytica live in the colon of mammals. Since these lack mitochondria, they do not have the pathways of aerobic respiration.
The pathways under aerobic respiration are:

• Glycolysis
• Krebs cycle
• Electron transport chain

In these organisms, which lack mitochondria, only the glycolysis pathway occurs. Since glycolysis can occur in the absence or presence of mitochondria, it occurs in these protozoa. The glycolysis pathway occurs in the cytosol while the Krebs cycle and the electron transport chain cannot occur in the absence of mitochondria.
The energy yield in these organisms would be much lower than the 38 ATP obtained in aerobic respiration. The pyruvic acid obtained at the end of glycolysis cannot be fully catabolized to obtain energy. These protozoa have a net gain of 2 ATP molecules in the pathway of glycolysis.
Hence, the organisms have a much lower energy yield.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 3FB
The initial catabolism of glucose occurs by glycolysis and/or the pentose phosphate and Entner Doudoroff pathways.
In the pentose phosphate pathway, the ATP (adenosine triphosphate) produced in this cycle is less than the 38 ATP molecules produced during glycolysis. This pathway produces two metabolites of ribose-5-phosphate and erythrose-4-phosphate, which are needed for the synthesis of nucleotides and amino acids.
The Entner Doudoroff pathway is an alternative to glycolysis in some organisms. This pathway gives lesser ATP than 38 ATP. A few bacteria like Pseudomonas aeruginosa and Enterococcus faecalis use the Entner Doudoroff pathway for the catabolism of glucose.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 3M
Carbohydrate catabolism begins with glycolysis:
Explanation
The catabolism of carbohydrates is the process where carbohydrates are broken down to produce ATP (adenosine triphosphate). Most of the carbohydrates are usually converted into glucose. The first step of glucose breakdown is the process of glycolysis.
In the process of glycolysis, glucose is converted into pyruvate. In this pathway, ATP molecules are produced. After glycolysis, the Krebs cycle, and the electron transport chain complete the total carbohydrate metabolism.
A diagram of glycolysis is given below:

Microbiology with Diseases by Taxonomy Chapter 5 Answers 3MC
Both anabolism and catabolism:
Anabolism is the synthesis of complex molecules or large molecules from simpler, smaller molecules. The process of catabolism is the breakdown of large molecules into smaller ones. In an amphibolic pathway, both these processes occur and energy is synthesized, and used up.
Hence, this option is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 3SA
Non-competitive inhibitor affect whole enzymatic pathway, at a single allosteric site:
Explanation
At an active site, competitive inhibitor binds, while a non-competitive inhibitor binds other than the active site. When a non-competitive inhibitor binds to an allosteric site, the active site of the enzyme is altered. A non-competitive inhibitor at a single allosteric site affects a whole pathway of enzymatic reactions.
Additionally, alteration of enzyme active site prevents the binding of the substrate. When the substrate prevents from binding to the enzyme, the reaction is inhibited. The inhibited reaction is a part of whole pathway; hence, remaining reactions do not take place. If the inhibited reaction is an important reaction in the pathway, the whole pathway comes to a stop.
In this way, the binding of a noncompetitive inhibitor at an allosteric site affects a pathway.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 4CT
A facultative anaerobe is grown in the same medium, but under different conditions. One culture is grown in the presence of oxygen while the second culture is grown in the absence of oxygen.
Of the two cultures, the culture exposed to air will have more cells at the end of the week.
As the species is a facultative anaerobe, it grows better in the presence of oxygen rather in the absence of oxygen.
The presence of oxygen enables the process of aerobic respiration in the culture. When aerobic respiration occurs, a high yield of 38 ATP (adenosine triphosphate) molecules is produced. Hence, this culture shows a higher rate of growth and division.
In the absence of oxygen, only glycolysis occurs. Glycolysis is followed by the process of fermentation occurs, which gives a much lower yield than 38 ATP. Hence, the culture under anaerobic conditions shows a lower rate of growth and division.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 4FB
The Krebs cycle or citric acid cycle is a series of eight chemical reactions used by all aerobic organisms to generate energy. This metabolic pathway involves oxidation of acetate derived from mainly carbohydrates, proteins, fats finally into carbon dioxide.
This pathway involved in the catabolism of acetyl-CoA and produces eight molecules of NADH (Nicotinamide adenine dinucleotide) and two molecules of FADH₂ (flavin adenine dinucleotide).
Hence, the correct option is Krebs cycle.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 4M
Saturation occurs when all active sites on enzyme molecules are filled:
Explanation
Enzymes have active sites, which bind to substrate molecules. When a substrate molecule binds to the active site of an enzyme, chemical reaction occurs that results in the formation of an intermediate complex. The complex consists of the enzyme and substrate.

Similarly, when all the active sites of an enzyme are filled with substrate molecules, it is known as saturation. On further addition of substrate molecules, the status of saturation does not change. Thus, on addition of enzyme molecules the situation of saturation is chnaged.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 4MC
Both anabolism and catabolism:
Anabolism is the synthesis of complex molecules or large molecules from simpler, smaller molecules. The process of catabolism is the breakdown of large molecules into smaller ones. In an amphibolic pathway, both these processes occur where energy is synthesized and also spent.
Hence, this option is incorrect.
Catabolism only:
The process of catabolism is the breakdown of large molecules into smaller ones. A good example would be the process of glycogenolysis. In this process, the large molecule of glycogen is broken down into small molecules of glucose. The process of catabolism is usually exergonic.
Hence, this option is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 4SA
The mechanism of negative feedback with respect to enzyme action:
Explanation
Negative feedback is also called feedback inhibition. The final product of a pathway is the inhibitor of previous reactions. Usually, the first enzyme of the pathway is inhibited by the final product. The negative feedback occurs only when the final product accumulates. The type of inhibition seen is usually allosteric inhibition.
The mechanism is shown in the following diagram:

A good example of the feedback inhibition is shown below:

Microbiology with Diseases by Taxonomy Chapter 5 Answers 5CT
The complete oxidation of a fat molecule with three chains containing 12 carbons each will give 305 ATP (adenosine triphosphate) molecules.
The break-up of these 305 ATP molecules is shown below:

• The glycerol moiety of the fatty acid enters the glycolysis pathway. The ATP gained from glycolysis is 2 ATP molecules.
• In the Krebs cycle, 4 NADH (Nicotinamide adenine dinucleotide) molecules are formed, which give a total of 12 ATP molecules since one NADH molecule gives 3 ATP molecules.
• In ??oxidation, each 12-carbon chain produces 5 NADH and 5 FADH₂ (flavin adenine dinucleotide) molecules.
• Since one NADH molecule gives 3 ATP molecules and one FADH₂ molecule gives 2 ATP molecules, the total number of ATP molecules from one chain would be 25. Three chains would give 75 ATP molecules.
• The acetyl CoA produced after ??oxidation is oxidized. Each chain produces 6 acetyl CoA molecules. Upon oxidation of one acetyl CoA molecule, 1 ATP molecule, 3 NADH molecules and 1 FADH molecule is produced.
• This gives a total of 12 ATP molecules per acetyl CoA molecule. Since 6 acetyl CoA molecules are produced per chain, the total number of ATP molecules per chain would be 72 ATP molecules.
• Three chains would give 216 ATP molecules.The total number of ATP molecules would be 2+12+75+216 , which gives 305 ATP molecules.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 5FB
The final electron acceptor in aerobic respiration is oxygen.
Aerobic respiration requires oxygen to generate energy in the form of adenosine triphosphate (ATP). Here, oxygen acts as final electron acceptor. Aerobic respiration is the method of pyruvate breakdown, which is generated from glycolysis and needs the entry of that pyruvate into mitochondria in order to be oxidized by the citric acid cycle or Krebs cycle.
The Krebs cycle is a series of eight chemical reactions used by all aerobic organisms to generate energy. This metabolic pathway involves oxidation of acetate derived from mainly carbohydrates, proteins, fats finally into carbon dioxide.
This pathway involved in the catabolism of acetyl-CoA and produces eight molecules of NADH (Nicotinamide adenine dinucleotide) and two molecules of FADH₂ (flavin adenine dinucleotide).
The NADH and FADH₂ produced in Krebs cycle undergo substrate level phosphorylation to generate ATP.
Hence, the correct answer is oxygen.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 5MC
Anabolism only involves the production of cell membrane constituents.
Anabolism only:
Anabolism is the synthesis of complex molecules or large molecules from simpler, smaller molecules. The cell membrane is also a complex molecule composed of many smaller molecules. The process of anabolism requires energy.
Hence, the correct answer is option (a) anabolic only.
Both anabolism and catabolism:
Anabolism is the synthesis of complex molecules or large molecules from simpler, smaller molecules. The process of catabolism is the breakdown of large molecules into smaller ones. In an amphibolic pathway, both these processes occur. The synthesis of the cell membrane does not come under the category of an amphibolic pathway.
Hence, the option (b) is incorrect.
Catabolism only:
The process of catabolism is the breakdown of large molecules into smaller ones. A good example would be the process of glycogenolysis. In this process, the large molecule of glycogen is broken down into small molecules of glucose. The synthesis of the cell membrane is not the breakdown of large molecules into smaller ones. Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 5SA
The metabolic pathways that allow facultative anaerobes to live under aerobic or anaerobic conditions:
Explanation
Facultative anaerobes exist under aerobic or anaerobic conditions. The metabolic pathways allow them to exist in the absence of oxygen by fermentation pathways.
The two common fermentation pathways are:

• Pyruvic acid to lactic acid
• Pyruvic acid to ethanol

Pyruvic acid is reduced to lactic acid with the help of NADH (reduced nicotinamide adenine dinucleotide), catalyzed by lactic dehydrogenase. NADH donates a proton to become NAD⁺ (oxidized nicotinamide adenine dinucleotide).

Initially, pyruvic acid is decarboxylated to form acetaldehyde. Acetaldehyde is reduced to form alcohol.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 6CT
A fever over 40⁰C is often life threatening in terms of its effect on the metabolism of the body.
Metabolism in any individual is mainly dependent on enzymes. Enzymes are usually proteins, which have a specific temperature range in which they can work best. Enzymes usually have an optimum temperature at which they work best.
So, if the temperature of the body rises above 40⁰C, most of the enzymes become inactive. Since they are proteins, the enzymes may also become denatured. When proteins become denatured, they cannot perform their normal function.
The folding or the conformation of the protein is very important to the function of the protein. Once the conformation of the protein is lost through denaturation, the function of the protein is also lost.
If most of the enzymes of the body stop functioning, the metabolism in the body will also eventually stop. This is why high fevers are life threatening.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 6FB
Three common inorganic electron acceptors in anaerobic respiration are NO₃^–, SO₄^2- and CO₃^2-.
In the process of anaerobic respiration, inorganic molecules are used as the final electron acceptor. Anaerobic respiration is mainly used by prokaryotes living in an anaerobic environment. The electron transport chain is also used in anaerobic respiration, but the final acceptors differ. The final acceptors are nitrate (NO₃^–), sulphate (SO₄^2-) and carbonate ions (CO₃^2-).
These electron acceptors used in anaerobic respiration have smaller reduction potentials when compared to oxygen. Hence, the yield of ATP (adenosine triphosphate) is lower than in aerobic respiration. The types of phosphorylation seen in anaerobic respiration are substrate level phosphorylation and oxidative phosphorylation.
These three electron acceptors are used as an alternative to oxygen.
Hence, the correct options are nitrate, sulphate, carbonate ions.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 6MC
Both anabolism and catabolism:
Anabolism is the synthesis of complex molecules or large molecules from simpler, smaller molecules. The process of catabolism is the breakdown of large molecules into smaller ones. In an amphibolic pathway, both catabolism and anabolism take place.
Hence, the option (b) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 6SA
Oxidation of molecule in the absence of oxygen:
Explanation
Oxidation of a molecule can occur in the absence of oxygen mediated by the process of fermentation.

1. Oxidation of a molecule occurs in the presence of oxygen, the products liberated are carbon dioxide and water.
2. Oxidation occurs in the absence of oxygen by the process of fermentation, the products liberated are organic waste products.

The process of fermentation is incomplete or partial oxidation of a molecule. Since, fermentation occurs in the absence of oxygen, the final electron acceptor cannot be oxygen in the electron transport chain. Organic molecules from the cell are used as the final electron acceptors instead of oxygen.
Additionally, the major advantage of fermentation is the production of ATP (adenosine triphosphate) in the absence of oxygen. The number of ATP molecules produced is less compared to aerobic oxidation. Thus, only 2 ATP molecules are produced.
The two common fermentation pathways are:

• Pyruvic acid to lactic acid
• Pyruvic acid to ethanol

Pyruvic acid is reduced to lactic acid with the help of NADH (reduced nicotinamide adenine nucleotide). NADH donates a proton to become NAD⁺ (oxidized nicotinamide adenine nucleotide). Pyruvic acid is decarboxylated to form acetaldehyde, which is reduced to form alcohol.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 7CT
Maximum number of ATP molecules generated by fat oxidation in bacteria:
Explanation
Cyanide is a toxic substance, which blocks cytochrome a₃. The cytochrome is present as the terminal electron acceptor before oxygen.
The diagram shown below is the action of cytochrome in ATP generation:

Similarly, due to the presence of cyanide, the electrons cannot pass from cytochrome a3 to oxygen. It results in the failure of the electron transport chain. The rest of the chain is not affected, but the functioning is stopped. ATP synthesis does not occur in presence of cyanide. The process of aerobic respiration does not occur and tissues depend on high supply of ATP to fail.
Additionally, organs like the heart and the central nervous system depend on a continuous supply of ATP. Such organs will immediately fail in the presence of cyanide. The redox state of ubiquinone in the presence of cyanide would be reduced in the presence of cyanide.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 7FB
Chemolithotrophs acquire electrons from inorganic compounds.
A lithotroph is an organism that uses inorganic substances as a source of energy. Chemolithotrophs are organisms that obtain their energy from the oxidation of inorganic reduced compounds.
In these organisms, the electron donors are oxidized in the cell. These electrons are later used to produce ATP (adenosine triphosphate). Most of these organisms can fix carbon dioxide through the Calvin cycle.
These organisms mainly grow in areas, where there is an abundance of inorganic compounds. The energy gained from these substances is less and this indicates that a large amount of substrate is needed to gain the energy required for the processes of the cell.
Hence, the correct answer is inorganic.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 7MC
Both anabolism and catabolism includes metabolism.
Both anabolism and catabolism:
Anabolism is the synthesis of complex molecules, or large molecules from simpler, smaller molecules. The process of catabolism is the breakdown of large molecules into smaller ones. In an amphibolic pathway, both these processes occur and energy is synthesized, and used up.
Hence, the correct answer is option (b).
Anabolism only:
Anabolism is the synthesis of complex molecules, or large molecules from simpler, smaller molecules. A good example would be glycogen, which consists of many glucose molecules. The process of anabolism is usually endergonic. The process of metabolism does not involve only anabolism, but catabolism also.
Hence, this option is incorrect.
Catabolism only:
The process of catabolism is the breakdown of large molecules into smaller ones. A good example would be the process of glycogenolysis. In this process, the large molecule of glycogen is broken down into small molecules of glucose. The process of catabolism is exergonic, and releases energy. The process of metabolism does not involve only anabolism, but catabolism also.
Hence, this option is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 7SA
Four groups of microorganisms that are photosynthetic are:
Heliobacteria:
Heliobacteria belongs to gram positive bacteria. The bacteria carry out photosynthesis in an oxygenic condition. The components used are present in the cytoplasmic membrane. An example is Heliobacterium.
Cyanobacteria:
Cyanobacteria are gram negative bacteria. The bacteria carry out photosynthesis in oxygenic conditions. These organisms are considered to be chloroplasts ancestors. An example is Oscillatoria.
Purple bacteria:
A purple bacterium is gram negative bacteria. The bacteria are used in the invaginations of the cytoplasmic membrane called lamellae. An example is Rhodobacteria.
Green bacteria:
Green bacteria are further divided into green sulfur and green non sulfur bacteria. All these bacteria are gram negative and carry out anoxygenic photosynthesis. These organisms contain chlorosomes. An example is Chlorobium.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 8CT
Similarities between photophosphorylation and oxidative phosphorylation:
Explanation
The similarity between photophosphorylation and oxidative phosphorylation is that both the processes pump protons across a membrane using energy. The concentration gradient, which develops is used to drive the synthesis of ATP (adenosine triphosphate).
Moreover, the synthesis of ATP usually occurs through membrane-bound enzyme ATP synthase. The source of energy is the difference between both processes. In photophosphorylation, light is the source of energy. The process is cyclic that works as long as light is present.
Thus, in the process of oxidative phosphorylation, the source of energy is obtained from the breakdown of biomolecules. The catabolism of molecules gives energy, which is then redirected into the process of oxidative phosphorylation.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 8FB
The enzyme of hydrolase adds a water molecule into the reaction. With the addition of the water molecule, the substrate is cleaved.
The enzyme isomerase plays a part of rearrangement of atoms in the molecule. A good example is triose phosphate Isomerase seen in the pathway of glycolysis.
The enzymes of ligase and polymerase play a role of joining two molecules together. A good example would be the process of replication of DNA (deoxyribonucleic acid), where both these enzymes are used.
The enzyme transferase moves functional groups from one substrate to another. A good example would be the transamination reactions.
The enzyme oxidoreductase plays a role in the oxidation and reduction of substances.
The enzyme lyase is usually used to cleave large molecules into smaller ones.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 8MC
Redox reactions are involved in the transfer of energy, transfer of electrons, oxidation, and reduction.
Redox reactions involve the processes of oxidation and reduction as seen in the name. They also involve the transfer of energy, and the transfer of electrons. The gain of electrons in reduction, and the loss of electrons in oxidation occur.
Hence, the correct option is (d) are involved in all of the above.
Transfer energy:
Redox reactions transfer energy from one molecule to another. In the process of oxidation and reduction, energy from one process is transferred to the other process. Redox reactions are also involved in the transfer of electrons, oxidation, and reduction reactions.
Hence, the option (a) is incorrect.
Transfer electrons:
Redox reactions transfer electrons from one molecule to another. In the process of oxidation and reduction, transfer of electrons occurs. Redox reactions are also involved in the transfer of energy, oxidation, and reduction reactions.
Hence, the option (b) is incorrect.
Involve oxidation and reduction:
In the process of reduction, electrons are gained while in the process of oxidation, electrons are lost. Both these processes occur in redox reactions.
Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 8SA
Oxygen is taken in to give carbon dioxide:
Explanation
During breathing oxygen is taken in to give carbon dioxide, the process is mediated by cellular respiration. Humans are aerobic organisms that need oxygen to breathe. The life cannot exist in the absence of oxygen for a long time.
Additionally, the oxygen we breathe is the final acceptor of the electron transport chain. The final product of the electron transport chain is water and carbon dioxide. Since, carbon dioxide is toxic to the body, released out through lungs.
Furthermore, oxygen is required for many processes of the body. Processes like cellular respiration or the catabolism of glucose need oxygen to undergo complete oxidation. In the presence of oxygen, one glucose molecule gives 38 molecules of ATP (adenosine triphosphate).
The diagram of the electron transport chain is shown below with the final acceptor as oxygen:

Microbiology with Diseases by Taxonomy Chapter 5 Answers 9CT
Pathogenic species of Haemophilus requires NAD⁺ and heme for growth:
Explanation
The pathogenic species of Haemophilus requires NAD⁺ (oxidized nicotinamide adenine dinucleotide) and heme for growth. The growth factors are needed from the host and help in growth of the pathogen. Moreover, NAD⁺ is an oxidizing agent, which accepts electrons from other molecules to reduce NADH (reduced nicotinamide adenine dinucleotide). The molecule then acts as a reducing agent to give electrons to other molecules. Hence, NAD⁺ is needed for electron transfer reactions.
Additionally, heme is required for heme containing molecules like cytochromes that are essential in the electron transport chain. Since, these molecules are essential in normal functioning of the pathogen, the pathogen obtains from surroundings.
Thus, the cytochromes have a heme group, which surrounds a metal ion. The metal ion present is iron, which keeps changing between reduced and oxidized states.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 9FB
The use of a proton motive force to generate ATP (adenosine triphosphate) is chemiosmosis.
In the process of chemiosmosis, the ions flow down their concentration gradient through an enzyme called ATP synthase. When ions flow through this enzyme ATP molecules are produced.
The process of chemiosmosis uses the potential energy of the electrochemical gradient present across membranes. This energy is used in the phosphorylation of ADP (adenosine diphosphate) to ATP.
In cells, the energy released in the electron transport chain is used to transport protons across a membrane. The transport of these protons across the membrane causes a proton gradient. This proton gradient generates proton motive force.
Hence, the correct answer is chemiosmosis.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 9MC

• Reduction is a chemical reaction that involves addition of hydrogen, or removal of oxygen from a compound. This reaction is opposite of oxidation. Therefore, a reduced molecule has gained electrons.
  Hence, the correct option is (a) has gained electrons.
• In the process of reduction, gain in electrons occurs. This gain causes the charge on the molecule to become negatively charged, but not positively charged. Only when a molecule loses electrons, it becomes positively charged. Since an electron is a negatively charged molecule, its gain makes molecules more negative.
  Hence, the option (b) is incorrect.
• In the process of oxidation, electrons are lost by the molecule. But the process of reduction involves the gain of electrons.
  Hence, the option (c) is incorrect.
• An electron donor is a molecule that donates an electron to another molecule. This molecule, which gains electrons, is reduced while the molecule donating the molecule is oxidized. A reduced molecule cannot be an electron donor.
  Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 9SA
Algae and cyanobacteria liberate oxygen and take in carbon dioxide:
Explanation
Cyanobacteria and alga take in carbon dioxide and give off oxygen as these organisms are photosynthetic. Moreover, cyanobacteria are gram negative bacteria, which carry out oxygenic photosynthesis. The organisms are considered to be the ancestors of chloroplasts. An example is Oscillatoria.
Similarly, the organisms like plants are capable in the process of photosynthesis. The organism like plants takes carbon dioxide and give off oxygen. Cyanobacteria do not have any special organelles like chloroplasts to help in photosynthesis. The cell membrane has invaginations, which function in photosynthesis.
Additionally, algae have plastids in their cells, which function in photosynthesis by taking in carbon dioxide and giving off oxygen. In contrast, some algae are in a symbiotic relationship with fungi, called as lichens.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 10CT
Comparison and contractions between aerobic respiration, anaerobic respiration, and fermentation:
Explanation

1. Aerobic respiration, fermentation and anaerobic respiration are processes, which occur in the cell. These processes produce ATP (adenosine triphosphate) from biomolecules. The process that produce highest yield of ATP is aerobic respiration.
2. In aerobic respiration, the three pathways that incorporate are glycolysis, Krebs cycle, and electron transport chain. The terminal electron acceptor in the electron transport chain is oxygen. The total yield of ATP seen in aerobic respiration is 38 ATP.
3. In anaerobic respiration, the terminal electron acceptor is organic molecules like nitrates and sulfates, but not oxygen. The yield of ATP is much lower than that of aerobic respiration.

In the process of electron transport chain the process of fermentation does not occur. ATP molecules are produced by substrate-level phosphorylation. The energy yield of ATP is much lower.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 10FB
The main coenzymes that carry electrons in catabolic pathways are NAD⁺ and FAD.
The electron carriers, which play a role in the electron transport chain, are NAD⁺ (Nicotinamide adenine dinucleotide) and FAD (Flavin adenine dinucleotide). When NAD⁺ goes through the electron transport chain 3 ATP (adenosine triphosphate) molecules are produced. When FAD goes through the electron transport chain 2 ATP molecules are produced.
These are produced as intermediates of the Krebs cycle and glycolysis. All these molecules combine to produce the 38 ATP molecules.
Hence, the correct answers are NAD⁺ and FAD.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 10MC
Activation energy does not require nutrients and water. Activation energy is the energy required for a reaction to occur. This activation energy is usually high for many reactions. It can be lowered by the presence of catalysts.
Hence, the option (b) is incorrect.
Activation energy does not result in the movement of molecules. Activation energy is the energy required for a reaction to occur. It can be lowered by the presence of catalysts. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 10SA
Carbon atoms of sugar catabolized, by Escherichia coli :
Explanation
The carbon atoms in sugar are catabolized by E. coli that is seen in the products of acids like formic acid, acetic acid, succinic acid, and lactic acid.
E. coli ferments sugar molecules to produce mixed acids. It can be shown as:

In E. coli, the first step is glycolysis. After the process of glycolysis, the pyruvate formed is converted into lactate, formate, succinate, ethanol, acetate, carbon dioxide, and water.

1. Lactate is formed from pyruvate by the enzyme lactate dehydrogenase. Acetyl CoA and formate are formed from pyruvate by the enzyme pyruvate formate lyase. Carbon dioxide and hydrogen are formed from formate catalyzed by formate hydrogen lyase.
2. Acetic acid is formed from acetyl CoA with the help of two enzymes phosphate acetyl transferase, and acetate kinase. Ethanol is formed from acetyl CoA with the enzyme alcohol dehydrogenase.
3. Succinate is formed from phosphoenol pyruvate. The enzyme fumarate reductase is used along with ATP synthase in a series of steps to form succinate.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 11CT
Metabolism of methanogenic prokaryotes in ocean sediments:
Explanation
Methanogenic prokaryotes are the organisms that live in ocean sediments. The scientists have estimated that about one-third of the biomass is present on Earth. Since, the organisms live in ocean sediments, they are usually anaerobic organisms. Moreover, the organisms do not depend on oxygen for their metabolic pathways.
Additionally, the organisms use hydrogen and carbon dioxide for their metabolic purposes. The carbon acts as a terminal electron acceptor instead of oxygen. The methanogenic prokaryotes produce methane as by-product, during metabolism and produce energy. Thus, the energy produced is used in different needs of the cell and responsible in degradation of organic matter.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 11MC
The catalytic activity of many enzymes is dependent on cofactors. Cofactors are either small organic molecules (called coenzymes), or metal ions. Coenzymes are freely diffusing organic molecules functions along with enzymes to carryout metabolic reactions. These coenzymes combine with the apoenzyme to form the holoenzyme.
Hence, the correct option is (d) are organic cofactors.
Coenzymes are not apoenzymes. Apoenzymes are the parts of enzymes that require cofactors. The combination of apoenzyme and cofactor make up the holoenzyme. Cofactors are also called coenzymes, but they cannot be apoenzymes.
Hence, the option (a) is incorrect.
Coenzymes are not proteins. They are organic cofactors. These cofactors can be inorganic ions. These cofactors combine with the apoenzyme to form the holoenzyme.
Hence, the option (b) is incorrect.
Coenzymes are not inorganic cofactors. They are organic cofactors. These cofactors combine with the apoenzyme to form the holoenzyme.
Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 11SA
Yeast cells make alcohol and cause bread to rise, due to fermentation:
Explanation
When yeast ferments the bread, it breaks down glucose into two molecules of alcohol and two molecules of carbon dioxide. This process is used in the process of making bread and in alcohol production.

Similarly, in the process of making bread, both the products are present in the bread. Since, the glucose is broken down by the yeast the products of alcohol and carbon dioxide is present in the bread. The alcohol is baked out of the bread, while the carbon dioxide is responsible for the rise in bread.
In the process of alcohol synthesis, the carbon dioxide formed from the reaction is released out of the alcohol. Sometimes, the carbon dioxide is used for carbonating specific beverages. The carbon dioxide is left inside the alcohol.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 12CT
Bacterium regulates the control in metabolic activities of the cell without a brain:
Explanation
The regulation seen in a bacterial cell can be controlled even in the absence of a brain. A variety of mechanisms are present, which plays an important role in regulation. Some of the mechanisms are:

• Inhibition in concentration of reactants and products.
• Presence of repressor molecules
• Presence of inhibitor or activator molecules

A good example would be feedback inhibition in which the product of a pathway inhibits the first enzyme of the pathway. This occurs when the product accumulates beyond a certain limit.
Therefore, phosphorylation and dephosphorylation are processes by which molecules are activated and deactivated. Another method is degeneration of proteins after their function is over.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 12MC
Hence, the correct option is (d).
Ribozymes are not proteins and they do not help in the production of ribosomes. They are enzymes, which process the synthesis of RNA (ribonucleic acid) molecules.
Hence, the option (a) is incorrect.
Ribozymes are composed of nucleic acids, but act enzymes. They do not produce ribose sugars, but process the synthesis of RNA molecules.
Hence, the option (b) is incorrect.
Ribozymes are enzymes, but do not store enzymes. Their main function is to process RNA molecules.
Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 12SA
Significant production of ATP in prokaryotic and eukaryotic cells:
Explanation

1. The most significant production of ATP (adenosine triphosphate) in prokaryotic cells is the cell membrane. The cell membrane of prokaryotes has all the necessary enzymes for ATP production and does not need a special organelle in this process.
2. The most significant production of ATP in eukaryotic cells is mitochondrion. The mitochondrion is a special organelle seen in eukaryotes. This organelle has its own DNA.

The parts of a mitochondrion are: Matrix, Cristae space, Outer membrane, Inner membrane, and Inter-membrane space
A diagram showing the structure of the mitochondrion is shown below:

Microbiology with Diseases by Taxonomy Chapter 5 Answers 13CT
When a bacterium uses the process of ??oxidation to break down a molecule of arachidic acid containing 20 carbons, the number of acetyl CoA molecules generated would be 10.
Each acetyl CoA molecule consists of 2 carbon atoms.

• When a fatty acid consisting of 20 carbon atoms undergoes the process of ??oxidation for the first round, it is broken down into one molecule of acetyl CoA molecule and an 18 carbon fatty acid.
• In the second round of ??oxidation, 18 carbons are broken down into one molecule of acetyl CoA and 16 carbons. In third round of ??oxidation, 16 carbons are broken into one molecule of acetyl CoA and 14 carbons.
• In the fourth round of ??oxidation, 14 carbons are broken down into one molecule of acetyl Co A molecule and 12 carbons. In the fifth round of ??oxidation, 12 carbons are broken down into one acetyl CoA molecule and 10 carbons.
• In the sixth round of ??oxidation, 10 carbons are broken down into one molecule of acetyl CoA and 8 carbons. In the seventh round of ??oxidation, 8 carbons are broken down into one molecule of acetyl CoA molecule and 6 carbons.
• In the eighth round of ??oxidation, 6 carbons are broken down into one molecule of acetyl CoA and 4 carbon fatty acid. In the ninth round of ??oxidation, the 4 carbon fatty acid is broken down into two molecules of acetyl CoA.

Thus, takes 9 ??oxidation cycles for 20 carbon fatty acid and broken down into acetyl CoA molecules.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 13MC
Ubiquinone does not affect the function of enzymes.
Ubiquinone:
The molecule of ubiquinone does not affect the function of enzymes. Ubiquinone is a carrier molecule in the transport of electrons in the electron transport chain. The electron transport chain does not affect the function of enzymes.
Hence, the correct option is (a) ubiquinone.
Substrate concentration:
The concentration of substrates in the medium affects the function of enzymes. When the substrate concentration is high, it binds to the active site of the enzyme and the product is formed. When the substrate concentration is lower than normal, the function of the enzyme is affected.
Hence, the option (b) is incorrect.
Temperature:
The temperature of the medium affects the function of the enzyme. Enzymes work best at their optimum temperature. Many enzymes have a temperature range at which they can function. If this range is crossed, the enzymes cease to function. Hence, the option (c) is incorrect.
Competitive inhibitors:
The presence of inhibitors also affects the function of the enzyme. In the presence of the substrate, the enzyme works perfectly. But, in the presence of competitive inhibitors, which compete with the substrate for the active site, the function of the enzyme is reduced.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 13SA
Vitamins are very much essential for the metabolism of microorganims. Microbes need the vitamins in trace amount. Most of the vitamins function as coenzymes. Coenzymes are organic molecules, which are covalently bound to the enzymes. Many coenzymes are synthesized from B vitamins.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 14CT

• Some desert rodents like Kangaroo rats that are able to live their entire lives without drinking any water. Kangaroo rats can survive on a diet of dry seeds and obtain all the moisture they need from their metabolic water. Their bodies are well adapted to the desert systems, which are highly efficient in conserving water.
• Kangaroo rats get all the water from their metabolic water, which is produced when their bodies break down food. They do not have sweat gland and do not sweat, preventing them from losing water due to evaporation, further more they have special oil glands on their backs that excretes oil to coat the fur , once again aiding in retaining water.
• Kangaroo rats have highly efficient kidneys that produce much more concentrated urine than most other mammals. Kidneys filter waste materials, water, and chemicals out of the body.
• Most of water is reabsorbed to the blood in the part of nephron called Loop of Henle and tis is found to be much longer in kangaroo rats than in other mammals.
• This extra-long Loop of Henle help in the absorption of more water, resulting in highly concentrated urine and prevent the water loss in Kangaroo rats.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 14MC
Hence, the correct option is (a) removal of hydrogen ions and electrons.
Removal of oxygen:
The removal of oxygen atoms does not indicate the process of oxidation. The process of oxidation is the donation of electrons or removal of electrons. In bacteria, hydrogen ions are transferred along with electrons in the process of oxidation. Hence, the option (b) is incorrect.
Addition of electrons and hydrogen ions:
The process of reduction is the addition of electrons. The removal of electrons occurs in the process of oxidation. In bacteria, hydrogen ions are transferred along with electrons in the process of oxidation.
Hence, the option (c) is incorrect.
Addition of hydrogen ions:
It does not occur in the process of oxidation. The removal of electrons occurs in the process of oxidation. In bacteria, hydrogen ions are transferred along with electrons in the process of oxidation.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 14SA
The cellular regulatory mechanism seen in this bacterium, which would explain the behavior, is the lac operon.
The lac operon is a set of genes which catabolize lactose. This operon is regulated by a regulator gene.
These genes are switched on only in the absence of glucose and presence of lactose. In the presence of glucose these genes are switched off. The various components of the lac operon are described below:
The regulator gene produces a repressor molecule, which binds to the operator region. This binding to the operator region inhibits the binding of RNA (ribonucleic acid) polymerase to the promoter region. This prevents transcription of the three structural genes.
In the absence of glucose and presence of lactose, a lactose molecule binds to the repressor and alters its conformation. This alteration prevents its binding to the operator region. This lets RNA polymerase bind to the promoter region and transcribe the three genes.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 15CT
Fatty acids contain even number of carbon atoms:
Explanation
Fatty acids usually have an even number of carbon atoms. This is because fatty acids are synthesized by adding two carbon atoms at a time. The catabolism of fatty acid occurs by cleavage of two carbons at a time. The two carbons are released as acetyl CoA molecules.
Synthesis:
In the synthesis of a fatty acid, a molecule of malonyl CoA is joined with a molecule of acetyl CoA. The malonyl CoA molecule is a three carbon compound, while acetyl CoA is a two carbon compound. Moreover, one carbon is lost as carbon dioxide leaving a 4-carbon compound. Furthermore, addition is made by malonyl CoA to add two carbon atoms to the chain and lose one carbon atom.
Catabolism:
In the process of ??oxidation, in every cycle, a two carbon fragment is cleaved from the fatty acid in the form of an acetyl CoA molecule. The ??oxidation cycle continues till whole fatty acid is broken down into acetyl CoA molecules.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 15MC
The fermentation of one glucose molecule under anaerobic conditions does not give a net gain of 4 ATP molecules. The process of fermentation of glucose gives 2 ATP molecules. Under aerobic conditions, one glucose molecule gives 38 molecules of ATP through the processes of glycolysis, Krebs cycle and the electron transport chain.
Hence, the option (b) is incorrect.
The fermentation of one glucose molecule under anaerobic conditions does not give a net gain of 38 ATP molecules. The process of fermentation of glucose gives 2 ATP molecules. Under aerobic conditions only, one glucose molecule gives 38 molecules of ATP.
Hence, the option (c) is incorrect.
The fermentation of one glucose molecule under anaerobic conditions does not give a net gain of 0 ATP molecules. The process of fermentation of glucose gives 2 ATP molecules. Under aerobic conditions only, one glucose molecule gives 38 molecules of ATP.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 15SA
Amination is the process of addition of an amino group to a molecule. Transamination is the transfer of an amino group from one molecule to another.
Amination is the reverse process of deamination. Deamination is the removal of an amino group from a molecule. One example of amination is:
Formation of aspartic acid from oxaloacetic acid:
An example of transamination would be the transfer of one amino acid to another. In this reaction the enzyme transaminase acts along with pyridoxal phosphate. The amino group from glutamic acid is transferred to oxaloacetic acid. The removal of an amino group from glutamic acid causes the formation of a-ketoglutaric acid.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 16CT
A molecule of glucose is catabolized by Embden-Meyerhof glycolysis and Krebs cycle. The number of molecules ATP, NADH, and FADH2 produced are, as follows:

• Glycolysis:
  • 2 ATP
  • 2 NADH
• Two pyruvate molecules to acetyl CoA:
  • 2 NADH
• Krebs cycle: ( for two pyruvate molecules)
  • 6 NADH
  • 2 ATP/GTP
  • 2 FADH₂

When a molecule of glucose is catabolized via the Entner Doudoroff pathway, and the number of molecules ATP, NADH, FADH2 produced are:

• Glycolysis:
  • 1 ATP
  • 1 NADH
  • 1 NADPH
• Two pyruvate molecules to acetyl CoA:
  • 2 NADH
• Krebs cycle: ( for two pyruvate molecules)
  • 6 NADH
  • 2 ATP/GTP
  • 2 FADH₂

Microbiology with Diseases by Taxonomy Chapter 5 Answers 16MC

• The complete oxidation of one glucose molecule under aerobic conditions gives a net gain of 38 ATP (adenosine triphosphate) molecules. Under aerobic conditions, one glucose molecule gives 38 molecules of ATP through the processes of glycolysis, Krebs cycle and the electron transport chain.
  Hence, the correct option is (c) 38.
• The complete oxidation of one glucose molecule under aerobic conditions does not give the net gain of 2 ATP molecules. Under aerobic conditions, one glucose molecule gives 38 molecules of ATP through the processes of glycolysis, Krebs cycle and the electron transport chain.
  Hence, the option (a) is incorrect.
• The complete oxidation of one glucose molecule under aerobic conditions does not give a net gain of 4 ATP molecules. Under aerobic conditions, one glucose molecule gives 38 molecules of ATP through the processes of glycolysis, Krebs cycle and the electron transport chain.
  Hence, the option (b) is incorrect.
• The complete oxidation of one glucose molecule under aerobic conditions does not give a net gain of 0 ATP molecules. Under aerobic conditions only, one glucose molecule gives 38 molecules of ATP.
  Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 16SA
The given diagram depicts the most important metabolic pathways like glycolysis, Kreb’s cycle, respiration, fermentation, and electron transport chain. The diagram with the appropriate labeled parts and the net gain of ATP (adenosine triphosphate) synthesized per stage is shown:

Here,
ATP= adenosine triphosphate,
NADH= Nicotinamide adenine dinucleotide,
FADH₂= flavin adenine dinucleotide.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 17MC
a) Its products are sometimes used to determine the presence of Pseudomonas :
A few bacteria like Pseudomonas aeruginosa and Enterococcus faecalis use the Entner Doudoroff pathway for the catabolism of glucose. Since, this pathway is seen only in a few bacteria, it is used as a criterion for distinguishing these bacteria from other microorganisms. Hence, the option (b) is incorrect.
b) It is a pathway of chemical reactions that catabolizes glucose:
The Entner Doudoroff pathway is a pathway which catabolizes glucose in some organisms. It is an alternative pathway for the catabolism or breakdown of glucose. This pathway gives lesser ATP than 38 ATP. Hence, this option is incorrect. Hence, the option (c) is incorrect.
c) It is an alternative pathway to glycolysis:
The Entner Doudoroff pathway is an substitute pathway to glycolysis. It does not give a high yield of 38 ATP after the catabolism of glucose. But, this pathway is seen in some organisms like Pseudomonas aeruginosa and Enterococcus faecalis. Hence, the option (d) is incorrect.
d) It is a series of reactions that synthesizes glucose:
The Entner Doudoroff pathway does not synthesize glucose. It is an alternative pathway for the catabolism or breakdown of glucose. This pathway gives lesser ATP than 38 ATP. Gluconeogenesis is a process in which glucose is synthesized from molecules like amino acids and fatty acids.
Hence, the correct option is (a) it is a series of reactions that synthesizes glucose.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 18MC
a) Krebs cycle:
The Krebs cycle is a light-dependent cycle. Glycolysis, Krebs cycle, and Electron transport chain are the light dependent cycles. When glucose is broken down using these three pathways, the net gain of 38 ATP molecules is achieved. The Krebs cycle does not have any light-independent reactions. Hence, the option (a) is incorrect.
b) Entner-Doudoroff pathway:
The Entner-Doudoroff pathway is not a light-independent pathway. It is an alternative pathway to glycolysis in some organisms. Since, glycolysis is a light-dependent pathway, Entner-Doudoroff pathway is also a light-dependent pathway. Hence, the option (b) is incorrect.
c) Pentose phosphate pathway:
The pentose phosphate pathway is not a pathway, which is independent of light. It is dependent on light. The ATP produced in this cycle is less than the 38 ATP molecules produced during glycolysis. This pathway produces two metabolites of ribose-5-phosphate and erythrose-4-phosphate, which is needed for the synthesis of nucleotides and amino acids. Hence, the option (d) is incorrect.
d) Calvin-Benson cycle:
The Calvin cycle is a light-independent cycle. In this pathway, carbon fixation occurs. The molecule of carbon dioxide is reduced to form glucose. This pathway uses ATP (adenosine triphosphate) and NADPH (reduced nicotinamide adenine dinucleotide phosphate) produced by the light-dependent reactions. Glyceraldehyde-3-phosphate is produced and enters a cycle that is reversal of glycolysis to generate glucose.
Hence, the correct option is (c) Calvin benson cycle.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 19MC
a) Amphibolic:
An amphibolic pathway is one in the reaction can proceed towards either catabolism or anabolism. The pathway of glycolysis is not an amphibolic pathway. Glycolysis is a catabolic pathway, which deals with the breakdown of glucose molecules. In catabolic pathway big and complex molecules are broken down to smaller and simpler molecules. Hence, the option (b) is incorrect.
b) Anabolic:
An anabolic pathway is one in which the synthesis of big and complex molecules occurs. Small and simple molecules are used to make the bigger and complex molecules. Glycolysis is a catabolic pathway, which deals with the breakdown of glucose molecules. Hence, the option (c) is incorrect.
c) Cyclical:
A cyclical pathway is one in which the ending product is used as a precursor. A good example is the Krebs cycle. In this cycle, acetyl CoA is the starting molecule and the product at the end is acetyl CoA. The intermediates of the cycle are important. Glycolysis is a pathway and not a cycle. Hence, the option (d) is incorrect.
e) Catabolic:
In catabolic pathway big and complex molecules are broken down to smaller, simpler molecules. In the glycolysis pathway, a molecule of glucose is broken down to produce pyruvate. In addition to pyruvate, ATP molecules are also formed which give energy to the cell.
Hence, the correct option is (a) catabolic.

Microbiology with Diseases by Taxonomy Chapter 5 Answers 20MC
a) In the use of oxygen:
Oxygen cannot be the difference between anaerobic respiration and anaerobic fermentation. Since, both the processes are anaerobic oxygen does not come into the process. Hence, the option (a) is incorrect.
b) That the former requires breathing:
Breathing comes under aerobic respiration, but not under anaerobic respiration. The difference between anaerobic respiration and anaerobic fermentation is that respiration requires breathing. Hence, the option (b) is incorrect.
c) Fermentation only produces alcohol:
The process of anaerobic fermentation produces alcohol and other by-products are also produced. A net gain of 2 ATP (adenosine triphosphate) molecules is produced. This is not the major difference between anaerobic respiration and anaerobic fermentation. Hence, the option (d) is incorrect.
d) The latter uses organic molecules within the cell as final electron acceptors:
A major difference between anaerobic respiration and anaerobic fermentation is the latter uses organic molecules within the cell as final electron acceptors. The process of anaerobic fermentation uses organic molecules present in the cell as electron acceptors. In the process of anaerobic respiration, inorganic molecules are used as the final electron acceptor.
Hence, the correct option is (c) the latter uses organic molecules within the cell as final electron acceptors.

Microbiology with Diseases by Taxonomy Chapter 4 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 4 Answers 1CM
Gram staining is a method that is used to differentiate bacterial species into gram-negative and gram-positive. This method was developed by Hans Christian Gram.
This staining method differentiates bacteria by the physical and chemical characteristics of the bacterial cell walls.
In this method a primary stain, a mordent (iodine), decolorizer and counter stain is used. A gram-positive bacterium appears in purple-blue color while gram-negative appears in pinkish-red color after staining.
The concept map which includes all the above terms is shown below:

Microbiology with Diseases by Taxonomy Chapter 4 Answers 1CT
Miss M. did a Gram stain in her practical class and came home with green fingers, and a low grade.
M must have mistakenly used another stain instead of crystal violet for the primary stain. The stain she used might have been malachite green. Malachite green is usually used in spore staining but not in Gram staining.
The procedure of Gram staining is:

1. A smear is made with culture on a glass slide.
2. The smear is air dried and heat fixed.
3. The smear is then flooded with the primary stain.
4. After some time, the stain is washed off and the smear flooded with the mordant.
5. The mordant is used to bind the primary stain to the cells.
6. The mordant is washed off and the decolorizer used.
7. After the decolorizer is washed off, the counter stain is used.
8. The counter stain is washed off and the cells viewed under the microscope.
9. If the cells are Gram positive cells, they are violet in color while Gram negative cells are seen in red color.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 1FB
The magnification of an object depends on both magnifying power of ocular and objective lenses. Moreover, the total magnification observed is the product of magnifying power of two lenses.
According to the given data, the power of the objective lens is 40X. Since, the power of the binocular lens is 15X, the following equation used is: Multiply 40 into 15 to get the value of 600X.
Magnification of an object is dependent on the following three factors:

• Thickness of the lens.
• Curvature of the lens.
• Speed of the light through the lens.

Different microscopes have different lenses with different magnifying powers, for different uses. Thus, an object magnifies 40X, each binocular lens magnifies 15X, and total magnification of the object being viewed is 600X.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 1L
According to the fig in Labeling 1, the photographs labeled are shown with corresponding type of microscope, they are as follows:

1. Scanning electron microscope.
2. Bright field microscope.
3. Phase contrast microscope:
4. Fluorescent microscope:
5. Transmission electron microscope:
6. Nomarski microscope:

Microbiology with Diseases by Taxonomy Chapter 4 Answers 1MC
The smallest unit is the nanometer among the given options of decimeter, millimeter, micrometer, and nanometer.
Nanometer: A nanometer is one-thousandth of a micrometer. A nanometer can also be written as 1/100,000,000 or 10-9 m. It is the smallest unit of length used. The unit of nanometer is used to determine the length of microorganisms in Microbiology. The diameter of a polio virus is measured in nanometers.
Hence, the correct answer is option (c) nanometer.
Decimeter: A decimeter is one-tenth part of a meter. A decimeter can also be written as 1/10 or 10-1 m. It is not the smallest unit of length used. The smallest unit of length is the nanometer. The unit of decimeter is rarely used to determine the length of microorganisms in Microbiology.
Hence, the option (a) is incorrect.
Millimeter: A millimeter one-hundredth part of a meter. A millimeter can also be written as 1/100 or 10-2 m. It is not the smallest unit of length used. The smallest unit of length is the nanometer. The unit of millimeter is used to determine the length of microorganisms in Microbiology. The diameter of a bacterial colony is measured in millimeters.
Hence, the option (b) is incorrect.
Micrometer: A micrometer is one-thousandth of a millimeter. A micrometer can also be written as 1/100,000 or 10-6 m. It is not the smallest unit of length used. The smallest unit of length is the nanometer. The unit of micrometer is used to determine the length of cells in Microbiology. The diameter of a white blood cell is measured in micrometers.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 1SA
The principle “electrons travel as waves” applies to electron microscopy.
Explanation
In light microscopes, only visible light can be used. Other frequencies of waves cannot be used. But in electron microscopes, electrons are used. These electrons travel as waves with wavelengths between 0.01 nm – 0.001 nm.
In addition, due to low wavelengths, the resolving power of electron microscopes is higher than that of light microscopes. When the resolving power of a microscope increases, the magnification power of the microscope also increases.
Furthermore, the electrons generated as a beam and the electrons behave in a similar way, as light waves. Since, the electron beams have lower wavelength than light waves, the images seen in the electron microscopes are more detailed than seen through light microscopes.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 2CT
The definition of species as “successfully interbreeding organisms” is not satisfactory for most microorganisms.
Interbreeding applies to humans as well as to some organisms, but it does not apply to microorganisms like bacteria. In bacteria, interbreeding can occur between two different species. Interbreeding does not necessarily need to be within a particular species. It can be outside the species in the case of bacteria.
Bacteria interbreed with other species through the process of asexual reproduction. This crossing of two different species produces a new species in the progeny. Bacteria also have a special characteristic where they can adapt plasmids from the surrounding environment. This helps them gain new characteristics.
Since bacteria do not stick to the definition of “successfully interbreeding organisms,” the definition does not hold good for them.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 2FB
The process of heat fixation can be described in the following way:

1. Small sample of the culture is taken and placed on a clean glass slide. If culture is in a broth, a small drop of the liquid is taken. If the culture is taken from a Petri plate, the culture is diluted in a drop of distilled water.
2. A smear is then made by spreading the bacterial cells across the glass slide.
3. The smear is air dried and then heat fixed.
4. In heat fixation, the slide is passed through the flame of a Bunsen burner. The smear is not directly passed through the flame. Only the opposite side of the glass slide is slowly passed through the flame.

Moreover, this technique was developed by Koch to fix the microorganisms firmly on the slide. This is because it prevents the cells from washing off during various procedures of staining. Thus, fixation of culture developed by Koch in bacteria was done by heat fixation.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 2MC
A nanometer is 1000 times smaller than a micrometer.
1000 times smaller: A nanometer is 1000 times smaller than a micrometer. A nanometer is one-thousandth of a micrometer. A nanometer can also be written as 1/100,000,000 or 10^-9 m. It is the smallest unit of length used.
Hence, the correct answer is option (d).
10 times larger: A nanometer is not 10 times larger than a micrometer. A nanometer is 1000 times smaller than a micrometer. A nanometer is one-thousandth of a micrometer. A nanometer can also be written as 1/100,000,000 or 10^-9 m. It is the smallest unit of length used. A micrometer can also be written as 1/100,000 or 10^-6 m.
Hence, the option (a) is incorrect.
10 times smaller: A nanometer is not 10 times smaller than a micrometer. It is 1000 times smaller than a micrometer. A nanometer is one-thousandth of a micrometer. A nanometer can also be written as 1/100,000,000 or 10^-9 m. A micrometer can also be written as 1/100,000 or 10^-6 m. It is the smallest unit of length used.
Hence, the option (b) is incorrect.
1000 times larger: A nanometer is not 1000 times larger than a micrometer. It is 1000 times smaller than a micrometer. A micrometer can also be written as 1/100,000 or 10^-6 m. A nanometer is one-thousandth of a micrometer. A nanometer can also be written as 1/100,000,000 or 10^-9 m. It is the smallest unit of length used.
Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 2SA
The definition of magnification given by a student is “magnification makes things bigger”.
Explanation
The process of magnification makes things looks bigger. But, the definition given by the student is false. This is because the process of magnification results, when light waves pass through the lens of the microscope. But, the things simply do not become bigger.
When light passes through a denser medium of glass, it refracts and bends. The refraction and bending of light rays, causes the magnification of the image. Thus, magnification of the image depends on the total magnifying power of the objective and the ocular lenses of the microscope.
The process of magnification depends on three factors:

• Thickness of lens.
• Curvature of lens.
• Speed of light through the lens.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 3CT
Taxonomy is the system of classification of organisms into different groups.
An example would be:

In taxonomy, we see the classification of an organism into different groups. In the above example, we see that the panther has some common characteristics with many groups. So, the main objective of taxonomy is to group all individuals having common characteristics into one class.
When new organisms are discovered, its characteristics are studied to see if they match the characteristics of the existing classes. If the organism has unique characteristics, then it is kept under a separate group.
With the exception of the discovery of new organisms, the present system of taxonomy is likely to remain the same. The main reason for this is that no one has found ambiguities in the present system so far.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 3FB
Immersion oil is used with 100X lens. When immersion oil is placed between the immersion lens and the slide, the light passing through the lens travels through the slide. In addition, no light rays refract between the lens and the slide. This increases the numerical aperture.
Resolution is the ability to distinguish two objects close to each other, the better the resolution, and the better is the image. When the numerical aperture is increased, the resolution of the microscope is also increased.
Thus, all the light rays coming from the source of light pass through the specimen, which helps to see the image better. No light rays are refracted on the increase of resolution.
Immersion oil increases the numerical aperture, which increases resolution because more light rays are involved.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 3MC
Resolution is best described as the ability to distinguish between two adjacent objects.
The ability to distinguish between two adjacent objects: Resolution is the ability to distinguish two objects, which are next to each other. The better the resolution, the better two objects can be distinguished. Resolution is also called the resolving power of a microscope.
Hence, the correct option is (c) the ability to distinguish between two adjacent objects.
The ability to view something that is small: Resolution is not the ability to view something that is small. It is the ability to distinguish two objects which are next to each other. Resolution is also called the resolving power of a microscope. The better the resolution, the better two objects can be distinguished.
Hence, the option (a) is incorrect.
The ability to magnify a specimen: The ability to magnify a specimen is known as magnification. Magnification is indicated by a number which is followed by the letter X. Resolution is the ability to distinguish two objects which are next to each other.
Hence, the option (b) is incorrect.
The difference between two waves of electromagnetic radiation: The difference between two waves in electromagnetic radiation is called wavelength. Electromagnetic radiation includes X-rays, microwaves and radio waves. All these waves differ in their wavelength. Resolution is the ability to distinguish two objects, which are next to each other.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 3SA
Electron microscopes can magnify only on dead organisms.
Explanation
Specimens are prepared, for viewing through electron microscopes and need to go through many processes. Very thin specimens are used, because they do not contain air molecules that can absorb electrons.
In addition, if whole cells are examined, the specimen needs to be dehydrated and embedded in plastic. Moreover, the cells are cut in an ultra-microtome to a thickness of 100 nm. These thin slices are then inserted into the microscope.
Since, vacuuming and slicing of the specimen is required, for every cell and tissue, living organisms cannot be studied under electron microscopes. The different processes of dehydration and sectioning are done to distort the specimen to some extent.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 4CT
A microbiology student says that the magnification of the microscope can be increased by adding immersion oil. This statement is wrong.
The oil immersion technique is used to increase the resolution of a microscope. When viewing a specimen without immersion oil, the light rays pass from the air into the glass slide. This change in the medium causes refraction and bending of the light rays.
To prevent this refraction, immersion oil is added. The immersion oil has a refractive index which is identical to that of the glass slide. So, since both the glass slide and the oil have the same refractive index, no refraction or bending of the light rays are seen.
This gives a clearer image of the object. This is the main purpose of oil immersion technique.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 4FB
The principle of contrast is used in phase microscopes like phase contrast and differential interference contrast microscopes.

• In phase contrast microscopes, the background of the object is dark, while the object is brightly lit. Some cell structures like cilia and flagella cannot be seen well in bright field microscopes. But, they can be seen in phase contrast microscopes. Phase microscopes use the principle of in-phase and out-of-phase waves. When light waves are in-phase, the image appears bright. When light waves are out-of-phase, the background appears dark, since the light waves cancel each other.
• In differential interference contrast microscopes, follows the same principle of phases of light waves. In addition, these microscopes also possess prisms, which split the light into component colors. This drastically increases the contrast of the image. A three-dimensional appearance is also seen.

Thus, contrast refers to the difference in intensity between two objects.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 4MC
Curved glass lenses both refract and bend light.
Refract: Curved glass lenses refract light. But they can also bend light. When a lens is curved, the light rays passing through the periphery are refracted more than the light rays passing through the center. This makes the light rays focus on a focal point. So, curved lenses can also bend light.
Hence, the option (a) is correct.
Bend: Curved glass lenses can bend light. But they can also refract light. The light rays bend when they enter a denser medium when compared to air. When light rays enter a lens, they bend due to the optical density of the lens. When these light rays leave the lens, they bend again. So, curved lens can also refract light.
Hence, the option (b) is correct.
Magnify: Magnification of an object can result when light rays enter a lens. The degree of magnification depends on the thickness of the lens, the curvature of the lens and the speed with which light is transmitted through the lens. The curvature of the lens is not the only criteria for magnification of an object.
Hence, the option (c) is incorrect.
Both a and b: The options of (a) and (b) are bending and refracting of light. Curved glass lenses have the properties of both bending and refracting light rays.
Hence, the correct option is (d) both a and b.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 4SA
The order of substances used in the Gram stain is, as follows:

• Primary stain
• Mordant
• Decolorizing agent
• Counter stain

The description of the process of Gram stain is, as follows:

1. A smear is made with culture on a glass slide.
2. The smear is air dried and heat fixed.
3. The smear is then flooded with the primary stain.
4. After some time, the stain is washed off and the smear flooded with the mordant.
5. The mordant is used to bind the primary stain to the cells.
6. The mordant is washed off and the decolorizer used.
7. After the decolorizer is washed off, the counter stain is used.
8. The counter stain is washed off and the cells viewed under the microscope.
9. If the cells are Gram positive cells, they are violet in color while Gram negative cells are seen in red color.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 5CT
The ocular lens of a light microscope has 10X magnifying power and 0.3 ?m resolution. When using the oil immersion lens, we cannot use the other ocular lenses of the microscope.
Since the resolution power of the microscope is 0.3 ?m, it indicates that when two objects are at a distance of 0.3 ?m, the microscope can detect them as two separate objects. By using the oil immersion lens, we are increasing the resolution of the microscope.
Since 400 nm and 40 nm are much greater distances than 0.3 ?m, we can resolve two objects at distances of 400 nm and 40 nm. By using the oil immersion lens, we can easily distinguish two objects at a distance of 400 nm and 40 nm.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 5FB
The principle of staining in microbiology is to use stains, which bind ionically to the cells. Stains are usually either positively charged or negatively charged.

1. Positively charged stains are called cationic chromophores.
2. Negatively charged stains are called anionic chromophores.

In the cell, structures like DNA (deoxyribonucleic acid) and proteins have negative charge. DNA contains phosphate in its background, which gives a negative charge. Proteins have charged amino acids, but they also contain phosphate bonds. Hence, both DNA and proteins come under negatively charged molecules.
Moreover, on trying to stain negatively charged organelles cationic chromophores are used. Positively charged structures are stained with anionic chromophores.
Thus, cationic chromophores such as methylene blue ionically bond to negatively charged chemicals, such as DNA and proteins.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 5MC
The factors which are important in making an image appear larger are the thickness, curvature of the lens, and the speed of light rays that passes through the lens.
The thickness of the lens: The thickness of the lens is an important factor in the magnification of an object. The thickness of the lens determines the speed of the light rays passing through the lens. But, the thickness of the lens is not the only factor responsible for the magnification of an object. The other factors are the curvature of the lens, and the speed of light rays that passes through the lens.
Hence, the option (a) is incorrect.
The curvature of the lens: The curvature of the lens is an important factor in the magnification of an object. The curvature of the lens refracts the light rays passing through the periphery of the lens. But, the curvature of the lens is not the only factor responsible for the magnification of an object. The other factors are the thickness of the lens, and the speed of light rays passing through the lens.
Hence, the option (b) is incorrect.
The speed of the light that passes through the lens: It is an important factor in the magnification of an object. But, the speed of the light that passes through the lens is not the only factor responsible for the magnification of an object. The other factors are the thickness of the lens and the curvature of the lens.
Hence, the option (c) is incorrect.
All of the above: All the above given options are correct. Each of the given options is important in the magnification of an image. In the absence of any one of the above factors, magnification of the object does not occur.
Hence, the correct option is (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 5SA
Latin is used in taxonomic nomenclature because of the following reasons:

1. The rules of nomenclature make it mandatory that all taxa should have Latin names.
2. The main language used by scientists during the time of Linnaeus was Latin.
3. Using the language of Latin is done to avoid making the national language of any country as the language of taxonomy.

Even though the common names of the organisms may differ from area to area, the scientific name remains unchanged. This preference for the language of Latin was seen during the time of Linnaeus.
Linnaeus suggested the binomial nomenclature in which every organism has two names – one is the genus name and the other is the species name. The scientific names can be given on the basis of different aspects.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 6MC
Resolution: The resolution in light microscopes is 200 nm to 10 mm. The resolution in transmission electron microscopes is 0.078 nm to 100 ?m.
Hence, the option (b) is incorrect.
Wavelengths: The light microscope uses light rays while electron microscopes use electrons. In light microscopes, the light rays pass through the specimen and in electron microscopes, a beam of electrons pass through the specimen.
Hence, the option (c) is incorrect.
All of the above: The differences between light microscopes and transmission electron microscopes are magnification, resolution, and wavelengths. Since, all these factors are covered in the above options, all of these options are correct.
Hence, the correct option is (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 6SA
The three characteristics of a specific epithet are given below:

1. The specific epithet is always written in lowercase letters.
2. The name is usually an adjective.
3. It is always written in italics.

The specific epithet is always written in lowercase letters according to the rules given by Linnaeus. Linnaeus also suggested that the species name should always be in italics along with the genus name.
The species name is usually an adjective, and can specify the nature of the organism, or can honor a particular scientist. A genus name can be common for few species, but a species name is always specific and unique for a specific organism.
When manually writing the genus and species names, they should be underlined.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 7MC
Simple microscope: A simple microscope does not produce a three-dimensional image. A three-dimensional image with a shadowed image is seen in a differential interference contrast microscope. These microscopes use prisms to split the light rays into different colors. Prisms are not used in simple microscopes.
Hence, the option (a) is incorrect.
Fluorescent microscope: A fluorescent microscope does not produce a three-dimensional image. A three-dimensional image with a shadowed image is seen in a differential interference contrast microscope. These microscopes use prisms to split the light rays into different colors. Prisms are not used in fluorescent microscopes.
Hence, the option (c) is incorrect.
Transmission electron microscope: A transmission electron microscope does not produce a three-dimensional image. A three-dimensional image with a shadowed image is seen in a differential interference contrast microscope. These microscopes use prisms to split the light rays into different colors. Prisms are not used in transmission electron microscopes. Electron microscopes use electron beams.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 7SA
The study of the nucleotide sequences of ribosomal RNA (ribonucleic acid) fits into a discussion of taxonomy.
The scientist Woese studied the sequences of the ribosomal RNA in different organisms. These sequences are usually present in all cells, and are vital for protein synthesis. This scientist found differences in the sequences of ribosomal RNA.
Based on these differences, Woese classified organisms into three groups:

• Eukarya
• Bacteria
• Archaea

The domain Eukarya contains eukaryotic ribosomal RNA sequences. The domains Bacteria and Archaea include all the prokaryotic cells. The ribosomal RNA sequences of these two domains differ from each other, and from eukaryotic rRNA sequences.
Hence, the rRNA sequences serve as a basis for the classification of cells into three domains.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 8MC
Phase-contrast microscope: These microscopes do not combine the greatest magnification with the best resolution. This is seen only in confocal microscopes. The usage of fluorescent dyes and combination of individual images is seen in confocal microscopes.
Hence, the option (b) is incorrect.
Dark-field microscope: These microscopes do not combine the greatest magnification with the best resolution. This is seen only in confocal microscopes. The usage of fluorescent dyes and combination of individual images is seen in confocal microscopes. In the dark-field microscope, a condenser is used, which is responsible for the contrast.
Hence, the option (c) is incorrect.
Bright-field microscope: The resolution and magnification in bright-field microscopes are not the highest. The usage of fluorescent dyes and combination of individual images is seen in confocal microscopes. The greatest magnification with the best resolution is seen only in confocal microscopes.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 8SA
A living cell can be magnified with an atomic force microscope, but cannot be viewed by electron microscopes or scanning tunneling microscopes.
In an atomic force microscope, a pointed probe is used to lightly touch the surface of the specimen. A laser beam is aimed at the tip of the probe. When this beam is deflected by the structure of the specimen, it is shown on a computer. The specimen does not need to be electrically conductive to be viewed by the atomic force microscope.
In electron microscopes, the processing of the specimen needs to be done. Since electrons are used, the instrument is under vacuum. The specimens must be dehydrated and sectioned for use. No air molecules should be present, which can deflect the electrons.
In scanning tunneling microscopes, a probe is used, which is kept at a distance from the specimen. The flow of electrons from the probe to the surface of the specimen is measured. Since electrons are used, the specimen needs to be processed specially.
Hence, due to the above reasons, live specimens cannot be viewed under electron microscopes or scanning tunneling microscopes.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 9MC
Negative stains such as eosin are also called capsule stains.
Capsule stains: Capsular stains are negative stains. They do not stain the microbe, but stain the surrounding medium. Eosin and nigrosin are used as negative stains. These are acidic stains, which are repelled by the charge on the cells and do not stain them.
Hence, the correct option is (a) capsule stains.
Endospore stains: Negative stains like eosin are not used in endospore staining. Negative stains do not stain the microbe, but stain the surrounding medium. They are acidic stains, which are repelled by the charge on the cells and do not stain them. Negative stains are used as capsular stains.
Hence, the option (b) is incorrect.
Simple stains: Negative stains like eosin are not used in simple staining. Negative stains do not stain the microbe, but stain the surrounding medium. In simple staining, the microbe is stained with only one stain. Negative stains are used as capsular stains.
Hence, the option (c) is incorrect.
Acid-fast stains: Negative stains like eosin are not used in acid-fast staining. Negative stains do not stain the microbe, but stain the surrounding medium. In acid-fast staining, an acid is used to make sure that the stain penetrates the cell. Negative stains are used as capsular stains.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 4 Answers 10MC
Domain: The domain to which the organism belongs is not written in lowercase letters. The first letter of the domain is capitalized and the rest of the letters are written in lowercase. An example is Bacteria. The specific epithet is always written in lowercase letters.
Hence, the option (b) is incorrect.
Genus: The genus to which the organism belongs is not written in lowercase letters. The first letter of the genus is capitalized, and the rest of the letters are written in lowercase. An example is Plasmodium. The specific epithet is always written in lowercase letters. Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 3 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 3 Answers 1CM
The following concept map illustrates the properties of gram positive and gram negative cell walls. The gram stain separates bacteria that have a thick layer of peptidoglycan as a cell wall, which stain purple, from gram negative bacteria, which have a thin peptidoglycan layer and an outer membrane, and stain pink.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 1CT
Golgi body is the shipping department of the cell. Large molecules from the cell are received, processed, and packaged for export by the Golgi body. The secretions of Golgi body packages are known as secretory vesicles. Golgi bodies are made up of flattened hollow sacs, which are circumscribed by a phospholipid bilayer.
Chemical that prevents the Golgi function leads to different problems in the human body such as respiratory, digestive, and hormonal issues.
The respiratory tract would dry out, making breathing and gas exchange more difficult. Lack of digestive enzyme secretion would lead to digestive problems. These affect the human body immediately.
It does not affect bacterial cells because they do not have Golgi bodies, as they are prokaryotes.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 1M

1. A gelatinous and sticky like substance that surrounds outside of the cell is known as glycocalyx. The literal meaning of glycocalyces is “sugar cup”. It is made up of polysaccharides and polypeptides, which protects the cell from drying. Glycocalyces of the pathogenic bacteria plays a vital role in the cell’s survival and disease causal. Sticky nature of the glycocalyx helps bacteria, to attach the surfaces.
   Hence, the term “Glycocalyx” perfectly matches the description (D) “sugar cup” composed of polysaccharides and or polypeptides.
2. Bacterial flagellum is made up of protein known as flagellin. They are long whip like structures, which extends to the surface of the cell. Flagella are composed of three parts. They are filament, hook, and basal body. Bacteria flagella sense external wetness and also inhibit their growth in dry habitats. Hook, rod, and rings together allow the filament to rotate 3600.Eukaryotic flagella are mainly composed of globular protein known as tubulin. The tubulin is arranged in chains to form hollow micro tubules. Nine pairs of the micro tubulins are surrounded by the two micro tubules in the center. This 9+2 arrangement of micro tubulins is present in all flagellated eukaryotic cells. Eukaryotic flagella are found at one pole of the cell.
   Hence, the term “Flagella” perfectly matches the description (B) long whip, (H) made of tubulin in eukaryotes, and (I) made of flagella in bacteria.
3. Bacterial flagella are long whip like structures, which extends at the surface of the cell. Flagella are composed of three parts. They are filament, hook, and basal body. Bacteria flagella sense external wetness and inhibit the growth in dry habitats. Hook, rod, and rings allow the filament to rotate 3600.Spirochetes are spiral shaped bacteria. They have flagella at both ends known as endoflagella. Axial filaments are placed between the cytoplasmic membrane and outer membrane. Axial filament is composed of endoflagella, which is revealed by the cross section of the spirochete. It rotates around the cell, causing the spirochete to give cross screw movement through its medium, which helps them to invade human tissues.
   Hence, the term “axial filaments” perfectly matches the description (F) responsible for motility of spirochetes.
4. Cilia are hair like structures that helps in movement of eukaryotic cells. They spread along the surface of the cell. They are not present in prokaryotes. They are composed of tubulin microtubules. Single cell may contain thousands of cilia. They arrange in‘9+2’pairs in their shafts and 9+0 triplets in their basal bodies.
   Thus, the term “Cilia” perfectly matches the description (H) made of tubulin in eukaryotes.
5. Fimbriae are rod like proteinaceous extensions in bacteria. Fimbriae are short, numerous, non-motile structures, that are sticky and bristle like projections. Bacterial cell contain hundreds of fimbriae. They play important role in bio-films.
   Thus, the term “Fimbriae” perfectly matches the description (A) bristle like projections found in quantities of 100 or more and (E) short, numerous, non-motile projections.
6. Pili are also known as conjugation pili. Pili are tubules containing a protein named pilin. They are longer than fimbriae, but shorter than flagella. They are not used in motility. They are mainly responsible in conjugation to transfer DNA from one cell to another cell.
   Hence, the term “Pili” perfectly matches the description (C) responsible for conjugation, (G) extensions not used for cell motility.
7. Archaeal have fimbriae and grappling hook like structures known as hami. It serves to anchor the cells to environment surfaces. They are bristle like projections, which are non-motile and have sticky rod shaped structure. Single archaeon have more than hundreds of hami on their surface.
   Thus, the term “Hami” perfectly matches the description of (A) bristle like projections found in quantities of hundred or more, (E) short, numerous, non-motile projections, and (G) extensions not used for cell motility.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 1MC
Facilitated diffusion is the process that allows large or charged chemicals to pass across the plasma membrane, down the chemicals electrical and chemical gradients.
(a)Active transport:
Active transport is a process of transporting molecules across the cell membrane. It uses transmembrane permease proteins. Some of these proteins are called as gated channels (ports). When cell needs substance then the proteins start functioning and open the gated channels, at normal time these channels are closed.
The permease that transports only one substance at a time is known as uniport permease and if a permease moves two substances in opposite direction that means one substance transported into the cell at the same time another substance transported out of the cell is known as antiports permease. Symports are single carrier proteins that allow transport of two molecules together across the plasma membrane in the same direction. Hence, this option is incorrect.
(b)Facilitated diffusion:
Electrically charged or large molecules are blocked by the phospholipid bilayer, so they do not cross the membrane. Cytoplasmic membrane contains proteins known as integral proteins; they act as carriers to move specific molecules to enter into or out of the cell through the process of diffusion. This process is termed as facilitated diffusion. Cell does not utilize its energy in facilitated diffusion. The electrochemical gradient provides the energy in this process. Some protein channels allow the passage of chemicals. Hence, this option is correct.
(c)Endocytosis:
Endocytosis is a type of active transport in which physical manipulation of cytoplasmic membrane around the cytoskeleton involved. This happens when the membrane expand to form pseudopodia surrounding the substance and engulfed into the cell. This process is termed as Phagocytosis, if the ingested particles are in the form of solid. If the engulfed particles are liquid in form, it is termed as Pinocytosis. Hence, this option is incorrect.
(d)Pinocytosis:
The incorporation of liquids into the cell by endocytosis is known as Pinocytosis. Endocytosis incorporates nutrients in to the cells and enclose in a food vesicle. Hence, this option is incorrect.
Hence, the correct answer is (b) Facilitated diffusion which is the process that allows large or charged chemicals to pass across the plasma membrane, down the chemicals electrical and chemical gradients.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 1SA
Diffusion down a concentration gradient:
Explanation
The net movement of a chemical from high concentration area to low concentration area is known as diffusion. It does not require energy, from the cell. Moreover, the process can undergo even in the absence of membranes by considering random walk in diffusing the particles. Thus, the process does not involve any chemical energy.
Additionally, chemicals that are lipid soluble can diffuse through lipid membrane, when they are small. For example, the smaller molecules that facilitate in the process of diffusion are: carbon dioxide, oxygen, alcohol, and fatty acids. These molecules freely diffuse through cytoplasmic membrane, whereas larger molecules like glucose and proteins cannot diffuse through diffusion.
Furthermore, diffusion brings nutrient and also removes (without spending energy) wastes from the cell. Its main function is to move molecules in or out of the cell. Thus, the process creates energy and other essential nutrients in a cell.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 2CT
Methylene blue is an aqueous or an alcoholic solution of a single basic dye. It is a heterocyclic aromatic chemical compound. It is a cationic dye with maximum absorption of light of about 670 nm.
It helps in study of different shapes of the cells and structures of the microorganisms. It mainly helps in examining DNA (deoxyribonucleic acid) or RNA (ribonucleic acid).
Mitochondria and nucleus are the two structures of yeast cell that get stained by Methylene blue due to the presence of DNA in them.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 2M

1. Ribosomes are large and complex molecules present in all prokaryotes and eukaryotes, function is protein synthesis. It contains two subunits. The large subunit joins the amino acids and forms the polypeptide chain. The smaller subunit is reads mRNA (messenger RNA).
   Bacterial cells have thousands of ribosomes in their cytoplasm that gives grainy appearance to cytoplasm. The size of the ribosomes and other cellular structures are expressed in Svedberg’s (S). Svedberg units determine the sedimentation rate. Ribosomes in prokaryotes are 70S and in eukaryotes ribosomes are 80S.
   Hence, the term “Ribosome,” perfectly matches the description (A) site of protein synthesis.
2. Internal network of fibers and tubules in eukaryotic cells is known as cytoskeleton. They plays important role in forming a base shape of cell. Moreover, acts as an anchor organelles and function in the movement of organelles within the cytosol.They allow contraction of the cell. They are composed of tubulin, micro tubules, thinner micro filaments, and intermediate filaments. They play vital role in the intra cellular transport and cellular division.
   The term “Cytoskeleton,” perfectly matches the description (d) allows contraction of the cell.
3. Centriole is a cylinder shaped cell structure. Some fungal cells and animal cells consist of two centrioles. Plants, algae, and fungi do not have centrioles. Centrioles consist of nine sets of tubulin microtubule triplets arranged in 9+0. It is seen in the base of eukaryotic flagella and cilia. They play important role in mitosis, cytokinesis, and formation of flagella and cilia.
   Thus, the term “Centriole,” perfectly matches the description (F) contains microtubules in “9+0” arrangement.
4. The largest organelle in the cell is known as nucleus. It is spherical in shape. Some cells have single nucleus and some other have multi nucleus. It is the site of DNA in eukaryotes. Nucleus is also known as the control center of the cell because it consists of genetic instructions in the form of DNA.
   Thus, the term “Nucleus,” perfectly matches the description (E) site of most DNA in eukaryotes.
5. Eukaryotic cells contain spherical and elongated structures known as mitochondria. Their membrane is made by the phospholipid bilayer. The folded membrane is called as cristae; it increases the inner membrane surface area. It is also called as power house of the cell because its cristae synthesize most of the ATP molecules in the eukaryotic cells.
   The term “Mitochondria,” perfectly matches the description (I) its internal membranes are sites for ATP production.
6. The light-harvesting structures present in the photosynthetic eukaryotes are known as chloroplasts. They have two phospholipid bilayer membrane and DNA. They produce few polypeptides by their own 70S ribosomes. Chloroplast pigments gather light energy to produce ATP from sugar and carbon dioxide.Thus, the term “Chloroplast” perfectly matches the description (G) light-harvesting organelle.
7. Net like arrangement of flattened hollow tubules in the nuclear envelope are known as endoplasmic reticulum. Endoplasmic reticulum transports the cytoplasm of eukaryotic cells. They function in the transport systems and are found in two forms. The smooth endoplasmic reticulum plays an important role in lipid synthesis and transport. Rough endoplasmic reticulum is made of ribosomes that are inserted in lumen and transported throughout the cell.
   Thus, the term “Endoplasmic reticulum,” perfectly matches the description (c) function as the transport system within eukaryotic cell.
8. Golgi body is a shipping department of the cell. It receives and packs large molecules, for export from the cell. The secretions of Golgi body packages are known as secretory vesicles. Golgi bodies are made up of flattened hollow sacs, which are circumscribed by a phospholipid bilayer.Thus, the term “golgi body,” perfectly matches the description (H) packages large molecules for export from the cell.
9. Peroxisomes are derived from endoplasmic reticulum. They have enzymes like oxidase and catalase. These enzymes degrade poisonous metabolic wastes (free radicals and hydrogen peroxide) which results from oxygen dependent reactions. Peroxisomes are present in all types of eukaryotic cells.
   Thus, the term “Peroxisomes,” perfectly matches the description (B) contains enzymes to neutralize hydrogen peroxide.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 2MC
The statement, “Growth and reproduction occurs simultaneously,” is true.
(a) Growth and reproduction may occur simultaneously in living organisms:
Increase in size of living thing is known as growth. All living things can grow. Non living things cannot grow. Living things are normally reproduce themselves. Reproduction is accomplished by either sexually or asexually. They increase in number and producing more organisms. Thus, the statement, “Growth and reproduction occurs simultaneously,” is a true statement. Hence, this option is incorrect.
(b) All living organisms must reproduce to be considered alive:
Increase in size of living thing is known as growth. All living things can grow. Non living things cannot grow. Living things are normally reproduce themselves. Reproduction is accomplished by either sexually or asexually. They increase in number and producing more organisms. Growth and reproduction may occur simultaneously in living organisms. A living organism must reproduce to be considered alive is false statement. Hence, this option is correct.
(c)Living things may stop growing and reproducing, yet still be alive:
All living things can grow, they can increase in size. Organisms have the ability to reproduce, they increase in number. Growth and reproduction may occur simultaneously in living organisms. If organism will died then growth and reproduction will be ceased. Living things may stop growing and reproducing yet still be alive is true statement. Hence, this option is incorrect.
(d)Normally, living organisms have the ability to grow and reproduce themselves:
Increase in size of living thing is known as growth. All living things can grow. Non living things cannot grow. Living things are normally reproduce themselves. Reproduction is accomplished by either sexually or asexually. They increase in number and producing more organisms. Growth and reproduction may occur simultaneously in living organisms. Normally, living organisms have ability to grow and reproduce themselves is true statement. Hence, this option is incorrect.
Hence, the correct answer is (b) a living organism must reproduce to be considered alive is not true statement. Growth and reproduction occurs simultaneously.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 2SA
Flagellar arrangements in bacteria:
Explanation
The important structure used in the motility of bacteria is known as flagella. Flagella are used to move towards favorable environments like food or light. They are long structures, which extend the surface of the cell. Moreover, it senses the external wetness and inhibiting their growth in dry habitats.
Bacterial flagellum is composed of protein known as flagellin. They are made up of three parts; filament, hook, and basal body. Filament is long and thin, it about 20nm in diameter.
Hook and basal body are composed of different proteins. The hook, rod, and rings allow the filament to rotate 3600. Flagella that are spread across the surface of the cell are known as peritrichous and flagella arrange only at ends are known as polar flagella.
Spirochetes are spiral shaped bacteria. They have flagella at both ends known as endoflagella.
Axial filaments are placed between the cytoplasmic membrane and outer membrane.Axial filament is composed of endo-flagella, which is revealed by the cross section of the spirochete. It rotates around the cell, causing the spirochete to give cross screw movement through its medium, which helps them to invade human tissues.
Bacterial flagella rotate more than 100,000 rpm and it change from counter clockwise to clock wise direction. Flagella have receptors, which gives signals to flagella to adjust their speed and direction of rotation.
The flagella movement in response to stimulus is known as taxis. Light stimulus is known as phototaxis and chemical stimulus is known as chemotaxis.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 3CT

• Paul Ehrlich, a German physician, observed that chemicals with selective toxicity kills only pathogens and do not harm human cells. He identified a toxic molecule known as magic bullet, which specifically binds pathogens and destroy them. He was also successful in chemotherapy of sleeping sickness.
• Chemotherapeutic drug is a chemical substance, which is used in disease treatment. They have selective toxicity that kills or inhibit the microbial pathogen without harming human cells. The role of administration plays important role in chemotherapy. It is mainly used for cancer treatment.
• The drug is able to reach the site of infection. It shows adverse effect on different mechanisms of the bacterial cell, such as protein synthesis, cell wall synthesis, nucleic acid synthesis, cell membrane synthesis, and other metabolic pathways. Examples of such drugs are penicillin, sulfonamides, streptomycin, and cephalosporin.
• Drug targeting biochemicals are toxic to bacteria, but not to human cells. Since the metabolic pathways present in the bacteria are different from human metabolic pathways, they inhibit only bacterial cell.
• The bacteria cells are different from human cells in many aspects. They contain cell wall, but human cells do not. Therefore, these drugs can act only on bacterial cells and destroy them without effecting human cells.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 3MC
The important structure of bacteria is known as flagella. It mainly used for the move towards food or light. Flagella are a long structure that extends the surface of the cell.
(a) Archaeal flagella:
Archaeal flagella resembles to the bacterial flagella. It contains basal body, hook, and filament. They are 10-14nm in diameter. They can grow with addition of subunits at the base of the filament. Their flagella are attached by the sugar molecules. Their energy is stored in molecules of ATP (Adenosine Triphosphate). They can rotate both clockwise and counterclockwise directions. Hence, this option is incorrect.
(b) Bacterial flagella:
The most important structures that are used for the motility of bacteria are known as flagella. Flagella are mainly used to move towards favorable environments like food or light. They are long structures which extend the surface of the cell. It senses the external wetness and inhibiting their growth in dry habitats. Hence, this option is incorrect.
(c) Eukaryotic flagella:
Eukaryotic flagella differ in structure and function from prokaryotic flagella. They attach within the cytoplasmic membrane. Their internal structures push cytoplasmic membrane out around them. Eukaryotic flagella are mainly composed by the globular protein known as tubulin.
This tubulin is arranged in chains to form hollow micro tubules. Nine pairs of the micro tubulins are surrounded by the two micro tubules in the center. This 9 + 2 arrangement of micro tubulins is present in all flagellated eukaryotic cells. Hence, this option is correct.
(d) All prokaryotic flagella:
Examples of Prokaryotic flagella are bacterial flagella and archaeal flagella. Bacterial flagella are long structures which are extended the surface of the cell. Flagella composed of three parts. They are filament, hook and basal body. Archaeal flagella resembles to the bacterial flagella, consisting of a basal body, hook and filament. Archaeal flagella extend outside the cell and not covered by the membrane. Hence, this option is incorrect.
Hence, the correct answer is (c) Eukaryotic flagella which contain 9 + 2 arrangement of microtubules.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 3SA
Cytosol:
Explanation
Cytosol is defined as the liquid portion in the cytoplasm. It was first introduced by H.A Lardy in 1965. It is an intra cellular fluid. It contains water, suspended substances, ions, carbohydrates, proteins, lipids and wastes. The prokaryotic cytosol contains the cell’s DNA (deoxyribonucleic acid) in a region known as nucleoid. It contains 70% of the water.
In addition, prokaryotes do not have phospholipid membrane, which surrounds DNA. Single, circular DNA molecules are organized as chromosomes in the bacteria. Some bacteria like vibrio cholerae unusually have two chromosomes.
Furthermore, chemical reactions occur in cytosol; for instance, enzyme present within the cytosol function to synthesis amino acids and degrade sugar.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 4CT

• The diffusion of water molecules across a selectively permeable membrane is known as osmosis.
• Proteins, amino acids, salts, or glucose do not freely penetrate into the membrane, so they cannot diffuse.
• When solutions have same concentration on either side of a selectively permeable membrane they are called isotonic solutions.
• When the concentration of solutions is not equal, then the solution containing higher concentration of solutes is known as hypertonic and the solution containing lower concentration of solutes is known as hypotonic.
• Water molecules move based on the concentration gradient that is hypotonic solution to hypertonic solution.
  Some bacterial toxins cause the cells lining the digestive tract to secrete ions.
• This makes the contents of the track hypertonic. As these cells secrete salts, it induces the patient to lose more amount of water and make him/her to shrivel.
• The patient’s water balance will be disturbed or imbalanced and results in severe dehydration. This condition many even lead to death of the patient, it there is over dehydration.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 4MC
(a) Symports:
Active transport is a process of transporting molecules across the cell membrane. It uses transmembrane permease proteins. Some of these proteins are called as gated channels (ports). When cell needs substance then the proteins start functioning and open the gated channels, at normal time these channels are closed.
The permease that transports only one substance at a time is known as uniport permease. Symports are single carrier proteins that carry two molecules or substances across the plasma membrane in the same direction. Hence, this option is incorrect
(b) Antiports:
Active transport is a process of transporting molecules across the cell membrane. It uses transmembrane permease proteins. Some of these proteins are called as gated channels (ports). When cell needs substance then the proteins start functioning and open the gated channels, at normal time these channels are closed.
The permease that transports only one substance at a time is termed as uniport permease. If a permease moves two substances in opposite direction that means one substance transported into the cell at the same time another substance transported out of the cell is known as antiports permease. Hence, this option is incorrect.
(c) Carrier proteins:
The net movement of a chemical from high concentration area to low concentration area is known as diffusion. Carrier proteins are most associated with diffusion. It does not require energy from the cell. It occurs even in the absence of cells or membranes.
In addition, only small or lipid soluble chemicals are diffused across the lipid portion of the membrane. For example: oxygen, carbon dioxide, alcohol and fatty acids that can freely diffuse through cytoplasmic membrane, whereas molecules like proteins and glucose cannot diffuse. Hence, this option is correct.
(d) Endocytosis:
Endocytosis is a type of active transport in which physical manipulation of cytoplasmic membrane around the cytoskeleton involved. This happens when the membrane expand to form pseudopodia surrounding the substance and ingesting into the cell. It is termed as phagocytosis, if solid particles are ingested by the cell and it is termed as pinocytosis, if liquid is ingested by the cell. Hence, this option is incorrect.
Hence, the correct answer is (c) carrier proteins which are most associated with diffusion.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 4SA
The membrane below the glycocalyx and the cell wall is known as cytoplasmic membrane. It is also known as cell membrane or plasma membrane. Thickness of cytoplasmic membrane is 8nm and composed of phospholipids and proteins.
Cytoplasmic membrane structure is referred to phospholipid bilayer. Phospholipid molecule is bipolar. Cytoplasmic membrane of bacteria is composed of integral proteins. Peripheral proteins are attached loosely to the membrane on one or another side. Cell membrane proteins act as recognition proteins, enzymes, receptors and carries.
It controls the movement of substances in and out of the cell. The main function of the cytoplasmic membrane is to protect the cell from the surroundings. It also provides shape to the cell. It mainly involves in different cellular processes (cell adhesion, ion conductivity and cell signaling).

Microbiology with Diseases by Taxonomy Chapter 3 Answers 5CT
Central vacuole is the large organelle, which is surrounded by the second membrane. It is a prominent feature of many plant cells. Vacuoles are the membranous sacs. They play important role in the transfer and storage of chemicals within the eukaryotic cells.
Plants and algal cells contain large vacuoles in the center of the cell for storing lipids, starch, and other substances. The rest of the cytoplasm is pressed against the cell wall in a thin layer, so the central vacuole is very large.
Hence, the large organelle surrounded by the second membrane is central vacuole. It is the membrane responsible for the change in electrical charge from -70 millivolts to -90 millivolts.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 5MC
(a) Nucleoid:
The liquid portion of the cytoplasm is known as cytosol. The nuclear region in prokaryotic cytosol is known as nucleoid. Nucleoid has no membrane and it contains a single circular molecule of DNA (Deoxyribonucleic acid). They lack in phospholipid membrane, which surrounds this DNA. Hence, this option is incorrect.
(b) Glycocalyx:
A gelatinous and sticky like substance that surrounds outside of the cell is known as glycocalyx. The literal meaning of glycocalyxes is “sugar cup.” It is made up of polysaccharides and polypeptides and protects cells from drying. Glycocalyces of the pathogenic bacteria plays a vital role in the cell’s survival and disease causal. Sticky nature of the glycocalyx helps bacteria to attach the surfaces. It does not form pseudopodia for mobility of an organism. Hence, this option is incorrect.
(c) Cilia:
Cilia are hair like structures that helps in movement of eukaryotic cells. They spread along the surface of the cell. They are not present in prokaryotes. They are composed of tubulin microtubules. Single cell may contain thousands of cilia. They arrange in‘9+2’pairs in their shafts and 9 + 0 triplets in their basal bodies. Hence, this option is correct.
(d) Circular DNA:
Nucleus is the control center of the cell because it consists of genetic material in the form of DNA. Nucleoid is present in the nuclear region of the prokaryotic cytosol. It does not have membrane, but it consist of single circular DNA. Hence, this option is incorrect.
Hence, the correct answer is (c) Cilia which is not associated with prokaryotic organisms.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 5SA
Living things performs functions like growth, reproduction, metabolism, responsiveness, movement and respiration, which are absent in non living things. Living things are made up of one or more cells.
Growth: Increase in size of an organism is known as growth. All living things can grow and Non living things cannot. It results in to morphogenesis and differentiation.
Reproduction: Individual organisms are produced from their parents, is known as reproduction. It accomplished by either sexually (animals) or asexually (bacteria). They increase in number and producing more organisms.
Metabolism: All chemical reactions are involved in maintain the living state of the cell is known as metabolism. It controls the chemical reactions in an organism and cellular structure.
Responsiveness: Every living thing responds to its atmosphere. They can change internal and external properties based on the changing conditions around them. Living things can respond to temperature, light, and sound etc.
Movement: All living things can move from one place to another place.
Respiration: All things can breathe in order to carryout energy producing process.
Living things also shows variations from the non living things by the following properties. They are; survivability, genetic composition, mutation, evolution, cellular composition, development, homeostasis and organization.
These are the differences between the living things and nonliving things.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 6CT
Figure 3.2 represents the typical prokaryotic gram positive cell wall. The cell wall is thick and there is no indication of external lipid bi layer compared to the gram negative bacteria. In gram negative bacteria the cell wall is thin with external lipid bi layer.
Bacterial cell wall gives structure and shape to the cell and protects from osmotic forces. Bacterial cell walls are composed of peptidoglycan. It also resists antimicrobial drugs. It plays an important role in treatment of bacterial diseases with specific antibiotics.
Peptidoglycan is a complex polysaccharide and is composed of two types of sugar molecules, N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM). NAG and NAM are covalently linked by the chains, and they are joined by four amino acids. They cover the total surface of the cell.
Gram positive bacterial cell wall contain thick layer of peptidoglycan. It also contains a chemical known as teichoic acid, which helps in the passage of ions through the cell wall. In gram staining procedure, cell wall retains crystal violet dye, so they appear in purple color.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 6MC
(a) Svedbergs are not exact but are useful for comparisons: Bacterial cells have thousands of ribosomes in their cytoplasm that gives a grainy appearance to cytoplasm. The size of the ribosomes and indeed other cellular structures are expressed in Svedbergs (S). Svedbergs are determines the sedimentation rate during high-speed centrifugation. Ribosomes in prokaryotes are 70S and in eukaryotes ribosomes are 80S. They are not exact but are useful for comparisons if the false statement. Hence, this option is incorrect.
(b) Svedbergs are abbreviated “sv”:
Protein synthesis occurring in cells sites is known as ribosomes. In bacterial cytoplasm thousands of the ribosomes are present. The size of the ribosomes and indeed other cellular structures are expressed in Svedbergs (S). Svedbergs are determining the sedimentation rate. They are abbreviated “sv” is the false statement. Hence, this option is incorrect.
(c) Svedbergs are prokaryotic in nature but exhibit some eukaryotic characteristics:
Bacterial cells have thousands of ribosomes in their cytoplasm that gives a grainy appearance to cytoplasm. The size of the ribosomes and indeed other cellular structures are expressed in Svedbergs (S). Svedbergs are determines the sedimentation rate during high-speed centrifugation. Ribosomes in prokaryotes are 70S and in eukaryotes ribosomes are 80S. So they are prokaryotic in nature but exhibit some eukaryotic characteristics is the false statement. Hence, this option is incorrect.
(d) Svedbergs are an expression of sedimentation rate during high-speed centrifugation:
Bacterial cells have thousands of ribosomes in their cytoplasm that gives a grainy appearance to cytoplasm. The size of the ribosomes and indeed other cellular structures are expressed in Svedbergs (S). Svedbergs are determines the sedimentation rate during high-speed centrifugation. Ribosomes in prokaryotes are 70S and in eukaryotes ribosomes are 80S. So they are an expression of sedimentation rate during high-speed centrifugation is the true statement. Hence, this option is correct.
Hence, the correct answer is (d) they are an expression of sedimentation rate during high-speed centrifugation. Svedbergs are determines the sedimentation rate during high-speed centrifugation.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 6SA
Reproduction result in increasing in number of organism. Living things normally reproduce themselves. Growth and reproduction may occur simultaneously in living organisms. Living things stop growing and reproduction, yet still alive.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 7CT
The most important structures that are used for the motility of bacteria are known as flagella. Flagella are mainly used to move towards favorable environments like food or light. They are long structures, which extend beyond the surface of the cell. It senses the external wetness and inhibiting their growth in dry habitats.
Bacterial flagellum is composed of protein known as flagellin. They are made up of three parts; filament, hook and basal body. Filament is long and thin, and is about 20 nm in diameter.
Hook and basal body are composed of different proteins. The hook, rod and rings allow the filament to rotate 3600. Flagella that are spread across the surface of the cell are known as peritrichous and flagella arrange only at ends are known as polar flagella.
Bacterial flagella rotate more than 100,000 rpm and it can also change its direction from counter clockwise to clock wise. Flagella have receptors, which gives signals to flagella to adjust their speed and direction of rotation.
Hence, the long projections with basal body in the cell wall are known as flagella. It is a prokaryotic. The cell uses this structure mainly for motility.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 7MC
Bacterial cell walls are composed of peptidoglycan. It is a complex polysaccharide.
(a) The cell walls of Bacteria are composed of peptidoglycan:
Bacterial cell wall gives structure and shape to the cell and protects from osmotic forces. It also resists antimicrobial drugs. It plays an important role in treatment of bacterial diseases with specific antibiotics. Bacterial cell walls are composed of peptidoglycan.
Peptidoglycan is a complex polysaccharide and is composed of two types of sugar molecules, N-acetyl muramic acid (NAM), and N-acetyl glucosamine (NAG). NAG and NAM are covalently linked by the chains and they are joined by four amino acids. They cover the total surface of the cell. Hence, this option is correct.
(b) Peptidoglycan is a fatty acid:
Bacterial cell walls are composed of peptidoglycan. Peptidoglycan is not a fatty acid. Hence, this option is incorrect.
(c) Gram positive bacterial walls have a relatively thin layer of peptidoglycan anchored to the cytoplasmic membrane by teichoic acids:
Gram-positive bacterial cell wall contain thick layer of peptidoglycan. It also contains a chemical known as teichoic acid which helps in the passage of ions through the cell wall. In gram staining procedure, cell wall retains crystal violet dye, so they appear in purple color. Hence, this option is incorrect.
(d) Peptidoglycan is found mainly in the cell walls of fungi, algae and plants:
Bacterial cell walls are composed of peptidoglycan. Peptidoglycan is not fixed to fungi, algae, or plants but contain mostly in bacterial cells. Hence, this option is incorrect.
Hence, the correct answer is (a) the cell walls of Bacteria are composed of peptidoglycan which is a complex polysaccharide.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 7SA
All cells are described as either prokaryotes or eukaryotes. Bacterial cells are prokaryotic, and algae are eukaryotic organisms.
Both prokaryotic and eukaryotic cells are surrounded by a cell wall. Cell wall gives structure and shape to the cell and also protects from osmotic forces.
Diffusion is facilitated by the channel proteins that are present in both prokaryotes and eukaryotes.
Ribosomes are present in both prokaryotes and eukaryotes. They are made up of water and suspended proteins, carbohydrates, lipids and wastes. Cytoskeleton is present in both.
Eukaryotes have nucleus, lysosomes, golgi body, peroxisomes, endoplasmic reticulum, vacuoles, mitochondria, vesicles, and chloroplast, which are absent in prokaryotes.
Bacterial cell do not have membrane surrounding its genetic material, but it is present in algae cell.
Nucleus is present in the eukaryotes, but is absent in the prokaryotes. Eukaryotes have internal membrane that compartmentalized cellular function, but it is absent in the prokaryotes.
Translocation occurs in prokaryotes, but it is absent in the eukaryotes. Chloroplast is present in eukaryotes, whereas absent in prokaryotes.
Cilia is present in eukaryotes, but it was absent in prokaryotes. Eukaryotes are larger than prokaryotes.
These are the differences and similarities between the bacterial (prokaryotes) cells and algal (eukaryotes) cells.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 8CT
Phototaxis is a kind of locomotary movement of an organism, in response to the light stimulus. By this process, phototrophic organisms can move towards light to carryout photosynthesis most efficiently. In positive phototaxis, the organism moves towards the direction of increasing light intensity, and in negative phototaxis the movement is opposite.
Hence, as per this knowledge, I would arrange light equipment, and favorable environment in lab to encourage the growth of these organisms.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 8MC
(a) It forms pseudopodia for faster mobility of an organism:
A gelatinous and sticky-like substance that surrounds outside of the cell is known as glycocalyx. The literal meaning of glycocalyxes is “sugar cup”. It is made up of polysaccharides and polypeptides and protects the cell from drying.
Glycocalyxes of the pathogenic bacteria plays a vital role in the cell’s survival and disease causal. Sticky nature of the glycocalyx helps bacteria to attach the surfaces. It does not form pseudopodia for mobility of an organism. Hence, this option is correct.
(b) It can protect a bacterial cell from drying out:
A gelatinous and sticky like substance that surrounds outside of the cell is known as glycocalyx. The literal meaning of glycocalyces is “sugar cup”. It is made up of polysaccharides and polypeptides that protect the cell from drying. Hence, this option is incorrect.
(c) It hides a bacterial cell from other cells:
A gelatinous and sticky like substance that surrounds outside of the cell is known as glycocalyx. The literal meaning of glycocalyces is “sugar cup”. It is made up of polysaccharides and polypeptides and protects cells from drying. Glycocalyces of the pathogenic bacteria plays a vital role in the cell’s survival and disease causal. Sticky nature of the glycocalyx helps bacteria to attach the surfaces.
It also protects the bacteria from getting recognized by the defensive cells of host. Streptococcus pneumoniae and klebsiella pneumoniae protects against the defensive cells in the respiratory tract causing pneumonia. Hence, this option is incorrect.
(d) It allows a bacterium to stick to a host:
A gelatinous and sticky like substance that surrounds outside of the cell is known as glycocalyx. It is made up of polysaccharides and polypeptides and protects cells from drying. Glycocalyces of the pathogenic bacteria plays a vital role in the cell’s survival and disease causal. Sticky nature of the glycocalyx helps bacteria to attach the surfaces. Hence, this option is incorrect.
Hence, the correct answer is (a) it forms pseudopodia for faster mobility of an organism which is not function of glycocalyx.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 8SA

• Streptococcus pyogenes is a spherical shaped bacterium. They are gram positive facultative anaerobic bacteria.
• They are oxidase and catalase negative; occurring in pair and long chains; and they are nonmotile and non spore forming bacteria.
• These bacteria contain plasmids, cell wall, slime coat called capsule. They do not have vacuoles. And reproduce via conjugation and smaller in size.
• They are responsible for many human diseases example pharyngitis, impetigo and pyogenic infection. They are hemolytic streptococci of group A.
• They exhibit beta hemolysis on the blood agar because their capsule is made up of hyaluronic acid. They have ability to destroy red blood cells and white blood cells.
• Entamoeba histolytica is an anaerobic parasitic protozoan; they move by amoeboid motion. Their cysts are 10-20m in diameter. They cause the disease known as amoebiasis.
• This disease is transferred through contamination of food and water.This protozoan contains nucleus, rod shaped chromosomes and vacuoles. They do not conjugate. No cell wall is present in Entamoeba histolytica.
• They mainly infect the digestive track of humans. They form trophozoites and are excreted in feces. The trophozoites survive for weeks in moist conditions. The symptoms of amoebiasis are abdominal pain and diarrhea.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 9CT
Neisseria gonorrhoeae is gram-negative diplococcic bacteria. This bacterium causes the disease known as gonorrhea (a sexually transmitted infection). This strain of Neisseria is pathogenic because as mentioned in the lab report, this was identified in a biofilm. Recently it has been shown that Neisseria gonorrhoeae can produce biofilms both in human host and experimental chambers. They can colonize the mucous membrane of the reproductive tract by joining with fimbriae. If they do not have fimbriae, they are non-pathogenic.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 9MC
Bacterial flagella are anchored to the cell by a basal body.
(a) Are anchored to the cell by a basal body:
The most important structures that are used for the motility of the bacteria are known as flagella. Flagella are mainly used to move towards favorable environments like food or light. They are long structures, which extend the surface of the cell. Bacterial flagella are anchored to the cell by a basal body. It senses the external wetness and inhibiting their growth in dry habitats.
Bacterial flagellum is composed of protein known as flagellin. They are made up of three parts; filament, hook and basal body. Filament is long and thin, it about 20 nm in diameter. Hook and basal body are composed of different proteins. The hook, rod and rings allow the filament to rotate 3600. Hence, this option is correct.
(b) Are composed by hami:
The most important structures that are used for the motility of bacteria are known as flagella. Flagella are mainly used to move towards favorable environments like food or light. They are long structures which extend the surface of the cell. It senses the external wetness and inhibiting their growth in dry habitats.
Archaeal have fimbriae and grappling hook like structures known as hami. It serves to anchor the cells to environment surfaces. They are bristle like projections, which are nonmotile and have sticky rod shaped structure. Single archaeon have more than hundreds of hami on their surface. Hence, this option is incorrect.
(c) Are surrounded by an extension of the cytoplasmic membrane:
Eukaryotic flagella is differ in structure and function from prokaryotic flagella. They are attaching within the cytoplasmic membrane. Their internal structures are pushing cytoplasmic membrane out around them. Hence, this option is incorrect.
(d) Are composed of tubulin in hollow microtubules is a 9+2 arrangement:
Eukaryotic flagella is mainly composed by the globular protein is known as tubulin. This tubulin is arranged in chains to form hollow micro tubules. Nine pairs of the micro tubulins are surrounded by the two micro tubules in the center. This 9+2 arrangement of micro tubulins is present in all flagellated eukaryotic cells. Hence, this option is incorrect.
Hence, the correct answer is (a) bacteria flagella are anchored to the cell by a basal body which are useful in motility.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 9SA
Cilia are hair like structures that helps in movement of eukaryotic cells. It is structurally identical to the flagella. It is made up of group of organelles called undulipodia.
They spread along the surface of the cell, and are not present in prokaryotes. Cilia are also present in paramecium and epithelial cells of metazoans (digestive system and lungs).
They are composed of tubulin microtubules. Single cell may contain thousands of cilia. They arrange in‘9+2’pairs in their shafts and 9+0 triplets in their basal bodies.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 10CT
SER or smooth endoplasmic reticulum is an interconnected sac like organelle that performs many metabolic processes in a cell. This organelle synthesizes phospholipids, lipids, and steroids. And also carries out drug detoxification, steroid and carbohydrate metabolism.
If a researcher treats a cell to block the function of this organelle, it initially shows effect on the lipid synthesis, and later on steroid and carbohydrate metabolism.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 10MC
Cell Wall is an important cellular structure in classifying bacterial species as Gram- positive or Gram-negative.
(a) Flagella:
The most important structures that are used for the motility of bacteria are known as flagella. Flagella are mainly used to move towards favorable environments like food or light. They are long structures, which extend the surface of the cell. It senses the external wetness and inhibiting their growth in dry habitats. Hence, this option is incorrect.
(b)Cell wall:
Bacterial cell wall gives structure and shape to the cell and protects from osmotic forces. It also resists antimicrobial drugs. It plays an important role in treatment of bacterial diseases with specific antibiotics. Bacterial cell walls are composed of peptidoglycan.Peptidoglycan is a complex polysaccharide and is composed of two types of sugar molecules, N-acetyl muramic acid (NAM) and N-acetyl glucosamine (NAG). NAM and NAG are covalently linked by the chains and they are joined by four amino acids. They cover the total surface of the cell.Gram positive bacterial cell wall contain thick layer of peptidoglycan. It also contains a chemical known as teichoic acid, which helps in the passage of ions through the cell wall. Gram negative bacteria cell wall contains a thin layer of peptidoglycan and outer membrane composed of phospholipids and proteins. Outer leaflet is composed by lipopolysaccharides.In Gram staining procedure, the gram positive bacterial cells are appear in purple color and gram negative bacterial cells appear in pink color. Based on the structure of bacterial cell wall, the classification of bacterial species is classified either gram positive or gram negative.
Hence, the correct answer is (b) Cell wall
(c) Cilia:
Cilia are hair like structures that helps in the movement of eukaryotic cells. They spread along the surface of the cell. They are not present in prokaryotes. They are composed of tubulin microtubules. Single cell may contain thousands of cilia. They arrange in‘9 + 2’pairs in their shafts and 9 + 0 triplets in their basal bodies. Hence, this option is incorrect.
(d) Glycocalyx:
A gelatinous and sticky-like substance that surrounds outside of the cell is known as glycocalyx. The literal meaning of glycocalyxes is “sugar cup.” It is made up of polysaccharides and polypeptides. It protects the cell from drying. Glycocalyxes of the pathogenic bacteria plays a vital role in the cell’s survival and disease causal. Sticky nature of the glycocalyx helps bacteria to attach the surfaces. Hence, this option is incorrect.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 10SA
Any chemical reactions that are involved in maintaining the living state of the cell is known as metabolism. It controls the chemical reactions in an organism and cellular structure.
It is a unique process of living things. Non living things cannot metabolize. Metabolic energy is stored in the chemical bonds of the adenosine triphosphate (ATP).
It is divided in to two categories, anabolism and catabolism. Catabolism is defined as break down of molecules to obtain energy. Synthesis of all compounds needed by cell is known as anabolism.
Metabolism results in growth and development of living cells.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 11MC
(a) The bacterial cell wall of gram positive contain thick layer of peptidoglycan. It also contains a chemical known as teichoic acid, which helps in the passage of ions through the cell wall.
Gram negative bacteria cell wall contains a thin layer of peptidoglycan and outer membrane composed of phospholipids and proteins. Outer leaflet is composed by lipopolysaccharides. Thus, the given option, exterior of the cell is negative, when compared to the interior is false. Hence, the option (a) is incorrect.
(b) Gram negative bacteria cell wall contain thin layer of peptidoglycan and outer membrane composed of phospholipids and proteins. Outer leaflet is composed by lipopolysaccharides.
Gram negative bacteria have periplasmic space between outer membrane and cytoplasm. Periplasmic space consists of water, nutrients and cell secreted substances like proteins and digestive enzymes, which involves active transport. Thus, by means of facilitated diffusion the acid move is the wrong statement. Hence, the option (b) is incorrect.
(d) Gram negative bacteria cell wall contains a thin layer of peptidoglycan and outer membrane composed of phospholipids and proteins. Outer leaflet is composed by lipopolysaccharides. Gram negative bacteria have periplasmic space between outer membrane and cytoplasm.
Periplasmic space consists of water, nutrients and cell secreted substances like digestive enzymes and proteins which are involved in active transport. Phagocytosis involves the movement of the acid is false statement. Hence, this option (d) is incorrect.
(e) Gram negative bacteria cell wall contains a thin layer of peptidoglycan and outer membrane composed of phospholipids and proteins. Outer leaflet is composed by lipopolysaccharides. Gram negative bacteria have periplasmic space between outer membrane and cytoplasm.Periplasmic space consists of water, nutrients, and cell secreted substances like proteins and digestive enzymes, which involves active transport. Hence, this option (c) is correct.
Hence, the correct answer is (c) The acid moves by the active process such as active transport.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 11SA

• The most important structures that are used for the motility of bacteria are known as flagella.
• Flagella are mainly used to move towards food or light. They are long structures, which extend beyond the surface of the cell. It senses the external wetness and inhibiting their growth in dry habitats.
• Bacterial flagellum is composed of protein known as flagellin. They are made up of three parts; filament, hook and basal body. Filament is long and thin, it about 20nm in diameter.
• Hook and basal body are composed of different proteins. The hook, rod and rings allow the filament to rotate 3600.
• Flagella that are spread across the surface of the cell are known as peritrichous and flagella arrange only at ends are known as polar flagella.
• Bacterial flagella rotate more than 100,000 rpm and the direction can change from counter clockwise to clock wise direction. Flagella have receptors, which gives signals to flagella to adjust their speed and direction of rotation.
• The flagella movement in response to stimulus is known as taxis. Light stimulus is known as phototaxis and chemical stimulus is known as chemotaxis.
• Eukaryotic flagella differs in structure and function from prokaryotic flagella. They attach within the cytoplasmic membrane. Their internal structures push cytoplasmic membrane out around them.
• Eukaryotic flagella are mainly composed of globular protein known as tubulin.This tubulin is arranged in chains to form hollow micro tubules.
• Nine pairs of the micro tubulins are surrounded by the two micro tubules in the center. This 9+2 arrangement of micro tubulins is present in all flagellated eukaryotic cells.
• Eukaryotic flagella may be single or multiple and found at one pole of the cell. Comparative to prokaryotic flagella they move differently. They have both positive and negative phototaxis and chemotaxis.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 12MC
Gram-positive bacteria have thick cell wall, which contains teichoic acids. In gram staining procedure cell wall retains crystal violet dye, so they appear purple color.
(a) Have a thick cell wall, which retains crystal violet:
Bacterial cell wall gives structure and shape to the cell and protects from osmotic forces. It also resists antimicrobial drugs, which plays an important role in treatment of bacterial diseases with specific antibiotics. Bacterial cell walls are composed of peptidoglycan. Peptidoglycan is a complex polysaccharide and is composed of two types of sugar molecules, N-acetyl muramic acid and (NAM) N-acetyl glucosamine (NAG). In addition, the sugar molecules, NAG and NAM are covalently connected by chains, to join four amino acid residues to cover the total surface of the cell.
Moreover, thick layer of peptidoglycan is present in Gram positive bacterial cell wall. It also contains a chemical known as teichoic acid, which helps in the passage of ions through the cell wall. In gram staining procedure cell wall retains crystal violet dye, so they appear as purple color. Hence, the option (a) is correct.
(b) Contain teichoic acids in their cell walls:
Bacterial cell wall gives structure and shape to the cell and protects from osmotic forces. It also resists antimicrobial drugs. It plays an important role in treatment of bacterial diseases with specific antibiotics. Bacterial cell walls are composed of peptidoglycan.
Moreover, thick layer of peptidoglycan is present in Gram positive bacterial cell wall. It also contains a chemical known as teichoic acid which helps in the passage of ions through the cell wall. Hence, the (b) option is correct.
(c) Appear purple after staining:
Bacterial cell wall gives structure and shape to the cell and protects from osmotic forces. It also resists antimicrobial drugs. It plays an important role in treatment of bacterial diseases with specific antibiotics. Bacterial cell walls are composed of peptidoglycan.Moreover, thick layer of peptidoglycan is present in Gram positive bacterial cell wall. It also contains a chemical known as teichoic acid, which helps in the passage of ions through cell wall. In gram staining procedure cell wall retains crystal violet dye, so they appear as purple color. Hence, the option (c) is correct.
Hence, the correct answer is (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 12SA
All cells are described as either prokaryotes or eukaryotes. Prokaryotes are characterized in to two taxa they are Domain Archaea and Domain bacteria. Algae, protozoa, fungi animals and plants are eukaryotes.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 13MC
When nutrients and water get exhausted, gram positive bacteria form a unique structure known as endospores. They are dormant and resistant cells. They are viable, for over hundred years. They are highly durable and dehydration resisting bodies.
(a) When nutrients and water get exhausted, gram positive bacteria form a unique structure known as endospores. For example, bacillus and clostridium produce endospores. Endospores are dormant and resistant cells. They are viable for over hundred years. They are highly durable and dehydration resisting bodies. They have thick walls of peptidoglycan, DNA cells, and cytoplasm. They contain large quantities of dipicolinic acid, calcium, and DNA binding proteins. They are not reproductive structures. Hence, the option (a) is incorrect.
(b) When nutrients and water get exhausted, gram positive bacteria form a unique structure known as endospores. For example, bacillus and clostridium produce endospores. Endospores are dormant and resistant cells. They are viable for over hundred years. They are highly durable and dehydration resisting bodies. They are not produced by archaeal. Hence, the option (b) is incorrect.
(c) When nutrients and water get exhausted, gram positive bacteria form a unique structure known as endospores. For example, bacillus and clostridium produce endospores. Endospores are dormant and resistant cells. They are viable for over hundred years. They are highly durable and dehydration resisting bodies.
The process of endospores formation is known as sporulation. They are resistant to drying, heat radiation, and lethal chemicals. Endospores stay alive in water even when boiled for several hours. They produce deadly toxins that cause fatal diseases like anthrax and tetanus. Hence, the option (c) is incorrect.
(d) When nutrients and water get exhausted, gram positive bacteria form unique structures known as endospores. For example, bacillus and clostridium produce endospores. Endospores are dormant and resistant cells. They are viable for over hundred years. They are highly durable and dehydration resisting bodies. They have thick walls of peptidoglycan, DNA cells, and cytoplasm. They contain large quantities of dipicolinic acid, calcium and DNA binding proteins
Hence, the correct option is (d) endospores are dormant, resistant cells.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 13SA

• Fimbriae are rod like proteinaceous extensions in bacteria. Fimbriae are short, numerous, nonmotile structures, that are sticky and bristle like projections.
• Bacterial cell may contain hundreds of fimbriae. They are thinner and shorter than flagella. They are clearly seen under electron microscope.
• They are mainly useful for bacteria to attach surface. Fimbriae are located in either poles of a cell or spread total surface of the cell, and are mainly found in gram negative bacteria.
• Fimbriae and glycocalyx play important role in the formation of biofilms. Biofilms are slimy masses of microbes adhering to a substance by means of fimbriae and glycocalyx.
• Fimbriae act as electrical wires that conduct electrical signals among cells in the biofilms. Biofilms play important role in the human diseases and in industry.
• Bacteria in biofilms are communicated with chemicals and electrical signals, which help them to form 3-dimentional structure. Biofilms also increase the bacterial resistance to antibiotics. They cause bacterial infection in humans; examples are gum disease and serious lung infections.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 14MC
(a) DNA:
DNA(deoxyribonucleic acid) is a genetic material in almost all living organisms. Most of the DNA viruses are double stranded. The bases of the DNA are adenine guanine, cytosine and thymine. It contains millions of nucleotides. Moreover, it is found in chromosomes, mitochondria, and chloroplast. Hence, the option (a) is incorrect.
(c) Dipicolinic acid:
When nutrients and water get exhausted, gram positive bacteria form a unique structure known as endospores. For example, bacillus and clostridium produce endospores. Endospores are dormant and resistant cells. They are viable, for over hundred years. They are highly durable and dehydration resisting bodies. They have thick walls of peptidoglycan, DNA, and cytoplasm. They contain large quantities of dipicolinic acid, calcium, and DNA binding proteins. Hence, the option (c) is incorrect..
(d) Tubulins:
Eukaryotic flagella are mainly present in the globular protein, known as tubulin. This tubulin is arranged in chains to form hollow micro tubules. Nine pairs of the micro tubulins are surrounded by the two micro tubules in the center. The 9+2 arrangement of micro tubulins is present in all flagellated eukaryotic cells. Hence, the option (d) is incorrect.
(b) Sulfur globules:
Sulfur globules are the inclusions, found in the bacterial cytosol. They include reserve deposits of starch, lipids, and compounds containing nitrogen, phosphate, and sulfur. These chemicals are stored in cytosol. Presence of inclusions helps in the diagnosis of pathogenic bacteria. Most of the bacteria store carbon and energy in the form of glycogen molecules or lipid polymer called polyhydroxybutyrate. The inclusions present in the cyanobacteria store gases in protein sacs known as gas vesicles.
Hence, the correct option is (b) Sulfur globules.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 14SA

• The membrane present below the glycocalyx and the cell wall is known as cytoplasmic membrane. It is also known as cell membrane or plasma membrane.
• Thickness of cytoplasmic membrane is 8 nm and it is composed of phospholipids and proteins.
• Cytoplasmic membrane structure is referred to as phospholipid bilayer. Phospholipid molecule is bipolar.
• The phospholipid molecule that is attracted by water is known to have hydrophilic nature and the phospholipid molecule, which will be repelled by water, is known to have hydrophobic nature.
• Cytoplasmic membrane of bacteria is composed of integral proteins. Peripheral proteins are attached loosely to the membrane on one or another side.
• Cell membrane proteins act as recognition proteins, enzymes, receptors, and as carries.Cell membrane prevents the passage of substances into and out of the cell.
• It allows nutrients into the cell and sends wastes out of it. It also involves in synthesis of molecules for energy storage and harvest light energy in photosynthetic bacteria.
• The membrane is selectively permeable and allows only some substances to cross it. It prevents the crossing of other molecules.
• The two main factors that prevent a molecule from moving across a cell membrane are size and composition. Large molecules cannot move across the cell membranes.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 15MC
(a) Gram positive archaeal walls:
Archaeal gram positive have thick cell wall similar to gram positive bacteria. In gram staining procedure, cell wall retains crystal violet dye, so they appear in purple color. Hence, the option (a) is incorrect.
(b) Cytoplasmic membranes in eukaryotes:
Eukaryotic cytoplasm consists of fluid mosaic model of phospholipids and proteins. These membranes contain sterols like cholesterol that helps in strengthening and solidifying, when temperature rise and provide fluidity during the fall in temperature. Hence, the option (b) is incorrect.
(c) Golgi bodies:
Golgi body is a shipping department of the cell. It receives and packs large molecules, for export from the cell. The secretions of Golgi body packages are known as secretory vesicles. Golgi bodies are made up of flattened hollow sacs, which are circumscribed by a phospholipid bilayer. Hence, the option (d) is incorrect.
(d) Endospores:
When nutrients and water get exhausted, gram positive bacteria form unique structure known as endospores. For example, bacillus and clostridium produce endospores. Endospores are dormant and resistant cells. They are viable for over hundred years. They are highly durable and dehydration resisting bodies. They have thick walls of peptidoglycan, DNA (deoxyribonucleic acid), and cytoplasm. They contain large quantities of dipicolinic acid, calcium, and DNA binding proteins. Hence, the option (c) is incorrect.
Hence, the correct answer is (c) Endospores.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 15SA

• Passive transport does not utilize the energy from cell. The electro chemical gradient provides energy for passive transport. It includes diffusion, facilitated diffusion, and osmosis.
• The net movement of a chemical from high concentration area to low concentration area is known as diffusion.
• It does not require energy from the cell. This process can occur even when there are no cells and cell membranes.
  Only small sized and lipid soluble chemicals can diffuse through the phospholipid membrane.
  For example, oxygen, carbon dioxide, alcohol, and fatty acids can diffuse freely via phospholipid membrane, whereas molecules like proteins and glucose cannot diffuse.
• Diffusion is very important process in cell. It brings nutrient and also removes (without spending energy) wastes from the cell. Its main function is to move molecules in or out of the cell.
• Specific molecules can cross the cell membrane through protein channels by a process known as facilitated diffusion. It occurs by means of carrier protein.
• Facilitated diffusion does not utilize the energy present in the cell; instead, it obtains energy from the electrochemical gradient process. Some protein channels allow the passage of chemicals.
• It is also known as passive mediated transport. It allows passage of molecules and ions spontaneously across biological membranes.
• It mainly occurs either in biological membrane or aqueous compartment in organism.Passive transport is example for facilitated diffusion. Its main function is movement of sugars and amino acids through the cell membrane.
• The diffusion of water molecules through a semi-permeable membrane is known as osmosis. The semi permeable membrane allows only water; it does not allow the passage of ions and molecules (solute particles).
• Osmosis diffuses water from high concentration area to low concentration area.
• When the solutions present on either side of a selectively permeable have same concentration then those solutions are said to be isotonic.
• When the concentration of solutions is not equal, then the solution containing higher concentration of solutes is known as hypertonic.
• The solution having lower concentration of solutes is known as hypotonic. Water molecules move based on the concentration gradient, that is, hypotonic solution towards hypertonic solution.
• It plays important role in cell because it keeps cell alive. It keeps cells from lysing or shrinking. It distributes nutrients and allows release of metabolic wastes from the cell.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 16SA
Active transport is a process of transporting molecules across the cell membrane. It uses transmembrane permease proteins. Some of these proteins are called gated channels (ports). When cell needs substance then the proteins start functioning and open the gated channels; at normal time, these channels are closed.
The permease, which transports only one substance at a time, is known as uniport permease. It is named antiport permease, if a permease moves two substances in opposite direction that means one substance is transported into the cell, while another substance is transported out of the cell. Symports are single carrier proteins that transport two substances at-a-time in one direction through the membrane.
Group translocation is an active process and it takes place only in few bacteria. In this process, substances are transported actively across the membrane and are chemically changed. The membrane traps the substances inside the cell.
It is very efficient in bringing the substances into the cell. It also operate the external concentration of the chemicals that transport as low as one part per million (ppm). Fatty acids, carbohydrates, pyrimidines, and purines are transported into the bacterial cells through group translocation.
Endocytosis is a type of active transport, in which physical manipulation of cytoplasmic membrane around the cytoskeleton involved. This happens when the membrane expand to form pseudopodia, surrounding the substance to bring it inside the cell.
When any solid substance is brought into the cell through this process, it is termed phagocytosis and if any liquid substance is brought into the cell by this process, it is termed pinocytosis.
Exocytosis is a eukaryotic process, which is reverse to the endocytosis. It enables the substance to be exported from the cell.
Their vesicles contain substances fused with cytoplasmic membrane, dumping their contents to the outer side. They transport substances like wastes and secretions.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 17SA

• Active transport is a process of transporting molecules across the cell membrane using transmembrane permease proteins.
• Some of these proteins are called gated channels (ports). When cell needs substance these proteins start functioning and open the gated channels; at normal time, these channels are closed.
• The permease, which transports only one substance at a time, is known as uniport permease. It is named antiport permease, if a permease moves two substances in opposite direction that means one substance is transported into the cell, while another substance is transported out of the cell.
• Symports are single carrier proteins that transport two substances at-a-time in one direction through the membrane.
• The electro chemical gradient provides the energy needed for this transport. In this type of transport, both symport and antiport work at the same time and is known as coupled transport.
  For example, H⁺ ions move down its electro chemical gradient by facilitated diffusion and provide energy to transport glucose into the cell against the gradient.

Microbiology with Diseases by Taxonomy Chapter 3 Answers 18SA
Mitochondria and chloroplast are semi-autonomous, that is, they divide independently, but they depend on the cell for proteins. They contain small amounts of DNA (deoxyribonucleic acid) and 70S ribosomes. They synthesize polypeptides using ribosomes.
In 1938, Lynn Margulis proposed a theory known as endosymbiotic theory for formation of eukaryotic cells. Based on this theory, parasites loss their ability to exit independently, but they retained DNA, ribosomes, and cytoplasmic membranes. At the same time, the larger cells became dependent on the parasites for aerobic ATP (adenosine triphosphate) production.
Based on this theory, aerobic prokaryotes changed into mitochondria and their cytoplasmic membranes become cristae. This theory explains the presence of 70S ribosomes and circular DNA within mitochondria and chloroplasts.
This theory was not accepted by the universe because it did not explain the two membranes of nuclear envelope.

Microbiology with Diseases by Taxonomy Chapter 2 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 2 Answers 1CM
The following concept map shows how different organisms are related in the study of microbiology.
Here,
DNA-deoxyribonucleic acid
RNA-ribonucleic acid

Microbiology with Diseases by Taxonomy Chapter 2 Answers 1CT
Bacillus anthracis is a bacterium that causes disease called anthrax. It was first observed by the Koch, when he examined the infected blood of animals and found a rod shaped bacterium forming chains. He observed that the endospores within the bacterial cells, when injected in to mice, produced anthrax.
Anthrax primarily affects herbivorous animals. It is mainly infected by spores from the soil. Bacillus anthracis have an outer layer containing endospores. The endospores outer layer is made up of D-glutamic acid, which disguises the bacterium from immune surveillance. Due to this reason white blood cells are unable to destroy the endospores.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 1FB
The outer most electron of an atom is known as valence electron. The outer most shell of an atom is known as valence shell. The valence of an atom is defined as its joining capacity.
The valence shell is considered positive when it contains an extra electron to give up. The valence shell that has space to fill in electrons is considered as negative.
For example, calcium atom has two electrons in its valance shell, thus having a valence of +2. The oxygen has two spaces to fill its valence shell, thus having a valance of -2.
Hence, the correct option is valence shell.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 1MC
b. Neutrons
Niels H.D.Bohr was a Danish physicist. In 1913, he identified a simple model that has negatively charged subatomic particles known as electrons, which orbits a centrally located nucleus like planets in a miniature solar system. The nucleus is composed of protons and neutrons. Neutrons are subatomic particles with no electric charge. Neutrons play a key role in the production of nuclear power.
Hence, the option (b) is incorrect.
c. Electrons
Niels H.D.Bohr was a Danish physicist. In 1913, he identified a simple model that has negative charged subatomic particles known as electrons, which orbits a centrally located nucleus like planets in a miniature solar system.
Hence, the option (c) is incorrect.
d. Ions
An atom in which the total number of electrons is unequal to the total number of protons (either positive or negative electrical charge) is known as ion. If the neutral atom losses electron, it gains positive charge, is known as cation. An atom that gains electron and contain negative charge, is known as anion.
Hence, the correct option is (b) neutrons.

1. Polar covalent bonds,
2. Non-polar covalent bonds,
3. Ionic bonds.

1. Polar covalent bonds: electrons with unequal sharing between two atoms of a covalent bond are known as polar covalent bond. For example: Water molecule.
2. Non-polar covalent bond: chemical bond between atoms with similar electro- negativities is known as non-polar covalent bond. Hydrogen molecule, oxygen molecule and methane formaldehyde are few examples of non-polar covalent bonds.
3. Ionic bonds: The formation of a chemical bond through an electrostatic attraction between positive and negatively charged ions is known as Ionic bond. Sodium chloride & sodium iodide are the examples of Ionic bond.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 2CT
Dehydrogenation is a process of removal of hydrogen from a molecule. In this chemical reaction saturated fatty acid is converted into unsaturated fatty acid. In this reaction, the removal of hydrogen creates double, or triple bonds between the carbon atoms in the fatty acid.
Due to the presence of double or triple bonds, it is considered as unsaturated. So, the name dehydrogenation is appropriate for this chemical reaction.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 2FB
The type of chemical bond between atoms with nearly equal electro-negativities is called a non-polar covalent bond.
Explanation:
The attraction between the atom and electrons is known as electronegativity. So, greater the electronegativity of the atom, greater will be the attraction towards the electron. The bonds are equally shared among the electrons. In these atoms with equally shared electro-negativities, the electrons spend equal amounts of energy and time.
In addition, no poles are found. Thus, chemical bond between the atoms with similar electro negativities is known as non-polar covalent bond. Examples are hydrogen-hydrogen, oxygen-oxygen and hydrogen-oxygen.
In case of hydrogen-hydrogen, each of the atoms requires another electron to have stability and to fill vacant valence shell. Here, the two atoms form a covalent bond by sharing their electrons.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 2MC
b. Electrons
Niels H.D.Bohr was a Danish physicist. In 1923, he identified a simple model that has negatively charged subatomic particles known as electrons. It has negative charge. It is less massive with 0.00054 Daltons mass. Since the contribution of Electrons to the overall mass is negligible they are ignored during the atomic mass discussions.
Hence, the option (b) is incorrect.
c. Isotopes
Isotopes are the atoms of an element that differ only in the number of neutrons in their nuclei. Every isotopes of a given element has different atomic mass number. Hence, the option (c) is incorrect.
d. Protons and Neutrons
Niels H.D.Bohr was a Danish physicist. In 1913, he identified a simple model that has negatively charged subatomic particles known as electrons, which orbits a centrally located nucleus like planets in a miniature solar system. The nucleus is composed of protons and neutrons.Protons are subatomic particles with positive electric charge. Neutrons are subatomic particles with no electric charge. Neutrons play a key role in the production of nuclear power Protons and neutrons each have 1 atomic mass unit that is also known as dalton. The atomic mass of an atom most closely approximates the sum of the masses of all its protons and neutrons.
Hence, the correct option is (d) Protons and Neutrons.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 2SA

• Most of the organisms consist of 50-99% of the water in their mass. Water molecule has two polar covalent bonds that allow hydrogen bonding between water molecules and their neighbors.
• Water molecules are cohesive; they stick to one another through hydrogen bonding. Surface tension is a special characteristic of water that allows forming a thin layer on the surface of cells, which helps in transportation of dissolved materials into and out of a cell.
• It is an excellent solvent. It dissolves salt and electrically charged molecules due to its attraction towards both negative and positive charges.
• The liquid state of water remains the same across varied temperature levels unlike other molecules of its size. All living things require water in liquid form.
• It absorbs heat energy even without changing its own temperature. This absorbed heat energy is released, and evaporated on heating the water molecules.
• These properties help in moderating the temperature fluctuations, which controls the damage of organisms.
• Water molecules involve in many chemical reactions with in cells. They act as reactants in hydrolysis and products of dehydration synthesis.
• These are the properties of the water that is important to life.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 3CT
The H⁺ represents both hydrogen ion and proton. In chemistry,H⁺ represents hydrogen ion. In physics, H⁺ is represented as proton. Protons are subatomic particles with positive electric charge.
Both hydrogen ion and proton are oxidatively same. H₃O⁺ is denoted as the hydrated form of the proton. When a proton mixes with water molecule it forms the hydrogen ion. So, the two freshmen are correct.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 3FB
The principal short-term energy storage molecule in cells is Adenosine triphosphate.
Explanation:
Adenosine triphosphate (ATP) is a most important short term energy storage molecule in cells. It is one of the nucleoside triphosphate that is used as coenzyme in the cells. It is also used in signal transduction as a substrate with the help of kinases, which phosphorylates lipids and proteins.
When ATP phosphate bonds are broken, most of the energy is released by the phosphate bonds other than covalent bonds. So, the phosphate-phosphate bonds of ATP are called as high energy bonds.
Cells used structural ATP molecule in the form of coenzymes. Phosphate bonds of ATP are mainly used in synthesis reaction, locomotion and transportation of substances into and out of the cells.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 3MC
b. The number of electrons
Niels H.D.Bohr was a Danish physicist. In 1913, he identified a simple model that has negatively charged subatomic particles known as electrons, which orbit a centrally located nucleus like planets in a miniature solar system. Isotopes are having same number of electrons.
Hence, the option (b) is incorrect.
c. The number of neutrons
Niels H.D.Bohr was a Danish physicist. In 1913, he identified a simple model that has negatively charged subatomic particles known as electrons which orbits a centrally located nucleus like planets in a miniature solar system. The nucleus is composed of protons and neutrons.
Isotopes are the atoms of an element in that only the number of neutrons differs. Every isotopes of a given element has different atomic mass number. Isotope of iodine is differing from another in the number of neutrons.
d. Atomic number
An atomic number is the number of protons found in the nucleus, and is equal to the number of electrons per atom.Hence, the option (d) is incorrect.
Hence, the correct answer is (c) The number of neutrons.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 3SA

• Fats are made by the organisms via dehydration reactions, which form esters between three chainlike fatty acids and glycerol. Fats contain high energy, stored in their carbon-carbon covalent bonds.
• They play vital role as energy source in organisms. They are also known as triglycerides. They can be catabolized to provide energy for movement, synthesis and transport.
• Fatty acids are of three types, they are saturated, unsaturated and polyunsaturated fatty acids. Each fatty acid consists of 12-20 carbon atoms.
• They differ in the presence of double bonds between the carbon atoms.In saturated fatty acids, the single bonded carbon atoms with the exception of the terminal ones are covalently linked by two hydrogen atoms.
• They are found in animals, and are solid at room temperature because fatty acids can be closely packed.
• Unsaturated fatty acids comprise of one or more double bonds between adjacent carbon atoms. They are bent at every double bond so they cannot be packed closely. They remain liquid at room temperature.
• One fatty acid molecule with multiple double bonds is known as poly unsaturated fatty acids. Plants contain fats that are either unsaturated or polyunsaturated.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 4CT

• Proteins are complex organic molecules. They are composed of oxygen, hydrogen, carbon, nitrogen and sulfur. They are structural components in cell walls.
• They are primary structural material of hair, nails, and outer cells of skin, flagella and cilia.They play an important role in chemical reaction as a catalyst by increasing the speed of reaction.
• These catalysts are knows as enzymes. Proteins regulate the cell function.They act as channels and pumps that help in movement of substances in to or out of the cell.
• Proteins like antibodies and complement defend our body against microorganisms.Proteins are composed of hundreds to thousands of amino acids. Protein function is defined by its shape.
• If any interruption is occurred in the shape, disrupts its functionality. Shape is altered by amino acid substitution.
• Physical and chemical factors like heat, pH changes, concentration of salt interfere with hydrogen and ionic bonding that disturbs 3-dimentional structure of proteins. This process is known as denaturation.
• Denaturation of protein disrupts its function and its structure. Due this reason gelatin can be changed back to liquid, but the cooked (heated) egg cannot be brought back to its original form.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 4FB
The most common long-term energy storage molecule is fat.
Explanation:
Fats are made by the organisms via dehydration reactions, which form esters between three chain-like fatty acids and glycerol. Fats contain high energy, stored in their carbon-carbon covalent bonds.
They play a vital role as energy source in organisms. They are also known as triglycerides. They can be catabolized to provide energy for movement, synthesis, and transport.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 4MC
b. Formaldehyde
Formaldehyde is an organic compound, and an essential precursor to chemical compounds and other metals.
Hence, the option (b) is incorrect.
c. Water
Water is an essential inorganic compound having special properties like liquidity, solvent nature, and heat absorption and participation in different chemical reactions. It dissolves salts and other electrically charged molecules. Water molecules stick to one another by hydrogen bonding. It is a rich substance present in the organisms.
d. Steroid
It is a group of lipid. It helps in maintaining the structural integrity of membranes during temperature fluctuations. They play important role in the human metabolism. Some of the steroids can act as hormones.Hence, the option (d) is incorrect.
Hence, the correct answer is option (c) Water.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 4SA
Oxygen is a major constituent for all living organisms. It is colorless, odorless and tasteless with formula O2. It has strong oxidizing agent. It is a third most abundant molecule in the universe. 21% of oxygen is present in the atmosphere.
Atomic oxygen is very reactive, and it does not exist in nature for long time. The presence of many ultraviolet radiations results 96% of atomic oxygen in low earth orbit atmosphere.
Molecular oxygen is defined as a molecule composed of two oxygen atoms. It is color less, odor less and tasteless. It is present in both ocean and atmosphere.
The main difference between atomic oxygen and molecular oxygen is, atomic oxygen contain many oxygen atoms. Whereas molecular oxygen has many oxygen molecules that are made by two oxygen atoms are bound together.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 5CT
Amino acids are the building blocks of proteins. Cells need proteins to perform all basic functions. Proteins are involved in DNA (deoxyribonucleic acid) synthesis, cell metabolism, movement, and reproduction. Amino acids can come in one of two forms, L or D form. L and D forms are stereoisomers; the amino acids are mirror images of each other. D form amino acids bend light clockwise and L form amino acids bend light counter clockwise. Cells only use L form amino acids, and thus only make these internally.
In the lab when scientists synthesize amino acids, they come out in both L and D form. However, when cells make amino acids, they only make the form they use, the L form.
If amino acids recovered from space were found in L and D form, scientists would conclude that they were formed from non-metabolic processes, how they are in the lab on earth. However, if amino acids were found only in L form, there may be a possibility of extraterrestrial life being responsible for their creation, like how living things create L form amino acids on earth.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 5FB
Groups of atoms such as NH₂ or OH that appear in certain common arrangements are called functional groups.
Explanation:
Carbon atoms linked together in branched chains, unbranched chains, and in rings to provide the basic frame work of organic molecules. Atoms of other elements attach to these carbon frame work and form many compounds.
Atoms appear in common arrangements, which are known as functional group.
For example: –NH₂ is the amino functional group, present in all amino acids and –OH, the hydroxyl amino functional group found in all alcohols.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 5MC
a. Nonpolar covalent bond
The atoms are attracted for electrons; this attraction is known as electro negativity. Sharing of valance electrons by combining atoms to fill valance shells is known as chemical bond. Chemical bond between atoms with similar electro negativities is known as non-polar covalent bond. Examples are hydrogen-hydrogen, oxygen-oxygen and hydrogen-oxygen. They are relatively strong bonds. These bonds are not present in a molecule of water.
Hence, the option (a) is incorrect.
b. Polar covalent bond
Sharing a pair of electrons by two atoms is known as a covalent bond. In a polar covalent bond two atoms share electrons unequally. Water molecule is an example of polar covalent bond. They are relatively strong bond.
c. Ionic bond
The formation of a chemical bond through an electrostatic attraction between positive and negatively charged ions is known as Ionic bond. Sodium chloride and sodium iodide are the examples of compound having Ionic bond. These bonds are not present in a molecule of water.
Hence, the option (c) is incorrect.
d. Hydrogen bond
It is the electromagnetic attraction between polar molecules. In this bond electropositive hydrogen atom binds to highly electronegative atoms like oxygen, fluorine, and nitrogen. These bonds are not present in a molecule of water.
Hence, the correct answer is option (b) polar covalent bond.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 5SA
Most of the organisms consist of 50-99% of the water in their mass. Water molecule has two polar covalent bonds that allow hydrogen bonding between water molecules and their neighbors.
Water molecules are cohesive; they stick to one another through hydrogen bonding. It gives many special characteristics of water like surface tension that allows forming a thin layer on the surface cells.
Water is an excellent solvent. It dissolves salts and electrically charged molecules. Polarity of water molecules makes water an excellent solvent.
It absorbs heat energy. While heating the water molecules, they are eventually evaporated and absorb energy. Water can be involved in many chemical reactions with in cells.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 6CT
Base is a molecule, which binds with H⁺ when dissolved in water. Some are divided into cations and hydroxyl ions (OH-). Bases like house hold ammonia (NH3) is directly accepting hydrogen ion to form NH4⁺.
Common households like tooth paste is used for the treatment of bees and wasps poison. It resolves the symptoms quickly. Vinegar paste and baking soda are also used, as they help to neutralize the poison.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 6FB
The reverse of dehydration synthesis is hydrolysis.
Explanation:
In the reaction of synthesis, either the resulted product is large or forms complex molecules. Synthesis reaction in biochemistry is often considered as dehydration synthesis. In the reaction of dehydration synthesis, water molecule is formed by the combination of two small molecules with the help of a covalent bond.
The reverse of dehydration synthesis is known as hydrolysis. Hydrolysis is a common type of decomposition reaction in biochemistry. In hydrolysis reaction, a covalent bond in a large molecule is broken and ionic components of water are added to the products.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 6MC
b. Ionically bonded
Giving up of electrons from one atom to another atom is known as ionic bond. Example is sodium-chlorine; it is relatively weaker than covalent bond in aqueous environments. Hence, the option (b) is incorrect.
c. Electrolytes
An anion is an atom having an extra electron and gains negative charge. A cation has lost an electron and gains positive charge. The ionic bonding between these two types of ions makes salt. When cations and anions of salts dissociate from one another, and become hydrated, they are known as electrolytes.
Electrolytes stabilize various compounds, carry electrons and allow electrical gradients to exist within the cell. In water, anions and cations of salts disassociate from one another, and become surrounded by water molecules. In this state the ions are known as electrolytes.
d. Hydrogen bonds
It is the electromagnetic attraction between polar molecules. In this bond electropositive hydrogen atom binds to highly electronegative atoms like oxygen, fluorine, and nitrogen. These bonds are not present in a molecule of water.
Hence, the option (d) is incorrect.
Hence, the correct answer is option (c) Electrolytes.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 7FB
Reactions that release energy are called exothermic reactions.
Explanation:
Reactions that release energy are known as exothermic reactions. Exothermic means outside heating. Thus energy is released in the form of heat or sound or electricity or light.
In reverse synthesis reaction, the bond is broken between larger molecules to form small atoms, ions, and molecules. This process is termed as decomposition reaction. These reactions release more energy and are exothermic in action.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 7MC
b. Glucose + ATP → glucose phosphate + ADP
It is an exchange reaction. It is similar to both decomposition and synthesis reactions. It forms covalent bonds and involve in endothermic, and exothermic reactions. In this reaction, atoms move from one molecule to another molecule. Above reaction represents the phosphorylation of glucose.
Hence, the option (b) is incorrect.
c. 6H₂0 + 6CO₂ → C₆H₁₂O₆ + 6O₂
It is a synthesis reaction. It forms large and complex molecules. They require energy to break bonds in the reactants and form product. Above reactions represents an algae making their own glucose. In this reaction six water molecules plus six carbon dioxide molecules yield one molecule of glucose and six molecules of oxygen.
Hence, the option (b) is incorrect.
d. A + BC → AB + C
It is an exchange reaction. It is similar to both decomposition and synthesis reactions. It forms covalent bonds and involve in endothermic, and exothermic reactions. In this reaction atoms are move from one molecule to another molecule.Hence, the option (d) is incorrect.
Hence, the correct answer is (a) 6H₂0 + 6CO₂ → C₆H₁₂O₆ + 6O₂.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 8FB
All chemical reactions begin with reactants and result in new molecules called products.
Explanation:
Bonding or breaking of the chemical bonds is known as chemical reactions. In this process, reactants are changed into the products. The reactants are those that exist at the beginning of the reaction in the form of atoms, ions, or molecules. All chemical reactions result in the formation of products.
The atoms, molecules or ions are left after the reactions are known as products. Reactants and products are different in their physical and chemical characteristics.
For example: – hydrogen and oxygen are gases that possess different properties. The numbers of these atoms never change in chemical reaction. Atoms are neither destroyed nor created, but can only be rearranged.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 8MC
A carbonated cola beverage has a pH of 2.9, which means it is acidic. Acidic solutions have high concentrations of hydrogen ions, and low pH.
The answer is choice (a), It has a relatively high concentration of hydrogen ions.
Choice (b) would mean that the solution is basic, which is not true since the cola has a pH of 2.9. Choice (c) would mean that solution is neutral, since hydroxyl ions and hydrogen ions balance each other out to make water. Choice (d) is also incorrect since cola has a low pH and must not have a buffer.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 9FB
The pH scale is a measure of the concentration of hydrogen ions in a solution.
Explanation:
Hydrogen ion concentration in a solution is measured by using logarithmic pH scale. The term pH comes from potential hydrogen. When acidity increases, then pH value decreases. Each decrease in the total number of pH indicates a 10-fold increase in the acidity.
For example: A glass of grape juice contains pH of 3.0 that is ten times as many hydrogen ions as the same volume of tomato juice, which has a pH of 4.0. Tomato juice is thousand times more acidic than pure water, which has a pH of 7.0. Water is neutral because it dissociates into one hydrogen Cation and one hydroxyl anion.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 9MC
b. Fatty acids
Molecules formed from glycerol and three chainlike fatty acids are known as fats. Three types of fatty acids are found in nature, they are saturated, unsaturated and poly unsaturated fatty acids. More number of hydrogen atoms is present in the structural formulas of saturated fatty acids than the unsaturated fatty acids. Unsaturated fatty acids have double bonds. Poly unsaturated fatty acids as the name suggests have several double bonds. Proteins are not made up of fatty acids.
Hence, the option (b) is incorrect.
c. Nucleic acids
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are the two types of nucleic acids. They are very important for the cells and viruses. They are un-branched macro molecular polymers of nucleotides. Proteins are not made up of nucleic acids.
Hence, the option (c) is incorrect.
d. Monosaccharide
Monosaccharide is a simple sugar, which cannot be broken down by hydrolysis. They are white crystal solids having sweet taste. They are organic compounds that are soluble in water.
Example of monosaccharide is glucose and fructose. Proteins are not made up of monosaccharides.
Hence, the option (d) is incorrect.
Hence, the correct answer is option (a) amino acids.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 10FB
A nucleic acid containing the base uracil would also contain ribose sugar.
Explanation:
Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA) are the two types of nucleic acids. They are the important regulatory molecules in the cells and viruses. They are un-branched macro molecular polymers of nucleotides. Each of them is composed of ribose sugar or deoxyribose, ionized polymers, and nitrogenous base. Adenine, guanine, cytosine, thymine, and uracil are the five different bases available. DNA consists of A, G, C, and T nucleotides.
Nucleotide composed with ribose and uracil is a uracil RNA nucleotide or uracil ribonucleotide. A nucleotide made of adenine and deoxyribose is an adenine DNA nucleotide or adenine deoxyribonucleotide.
Ribose sugar is a main component of the nucleic acids, nucleotides, ATP (Adenosine triphosphate), chemicals, enzymes and vitamins. It is found in D-ribose. RNA is a nucleic acid based on the ribose sugar. The RNA component helps in genetic transformation. It is essential for all living organisms.

Microbiology with Diseases by Taxonomy Chapter 2 Answers 10MC
b. Carbohydrates
They are organic molecules composed of atoms of carbon, oxygen and hydrogen. They contain equal number of oxygen and carbon atoms, and many hydrogen atoms. They play important role in organisms. Carbohydrates like glucose are used for long-term storage of chemical energy. Monosaccharide, disaccharides and poly saccharides serve as energy sources, structural molecules and recognition sites during inter cellular interactions. All carbohydrates are not hydrophobic molecules.
Hence, the option (b) is incorrect.
c. Lipids
They are a diverse group of organic macro molecules, which are not composed of regular subunits. They are hydrophobic (insoluble in water) macro molecules. Lipids do not have affinity towards water because they are composed of carbon, and hydrogen atoms linked by nonpolar covalent bonds; they have no attraction to the polar bonds of water molecule. Fats, phospholipids, waxes and steroids form the four major groups of lipids in cell.
d. Nucleic acids
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are the two types of nucleic acids. They are very important for the cells and viruses. They are un-branched macro molecular polymers of nucleotides. Nucleic acids are hydrophilic in nature.Hence, the option (d) is incorrect.
Hence, the correct answer is option (c) Lipids.