Microbiology with Diseases by Taxonomy Chapter 11 Answers

Microbiology with Diseases by Taxonomy Chapter 11 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 11 Answers 1CT
Deeply branching bacteria:
Explanation
The description, deeply branching bacteria is not correct. This is because the student defined that deeply branching bacteria are bacteria that are believed to have branched off from early normal bacterial life. Moreover, they have characteristics that are similar to other bacteria, such as being autotrophs and being able to withstand extreme environments.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 1L
(b) Coccobacillus: these are both partially spherical and rod shaped.
(c) Bacillus: these are rod shaped bacteria.
(d) Vibrio: these are comma shaped.
(e) Spirillum: these are stiff and spiral.
(f) Spirochete: these are flexible and spiral.
(g) Pleomorphic: these have different shapes.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 1M
Bacillus anthracis :
Explanation
Koch was a German physician, played an important role in establishing microorganisms to cause specific diseases. Moreover, he demonstrated certain bacteria known as Bacillus anthracis that is present in the blood of animals, but absent in healthy animals. He demonstrated that bacterium would cause anthrax by specific microorganisms Bacillus anthracis.
Bacillus anthracis is an agent of bioterrorism. It is facultative anaerobic rods and an endospore former. The endospores are either inhaled or enter the body through breaks in the skin. When they germinate vegetative cells produce toxins that kill surrounding tissues.
Hence, the bacterium, “Bacillus anthracis”, matches with the term, “anthrax.”
Thus, the correct option is (E) anthrax.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 1MC

  • Snapping division is a type of binary fission with small variation. In snapping division only the inner portion of the cell wall forms a cross wall. This thickening of new transverse wall put tension on the outer layer of the old cell wall. And the tension swaps outer wall and it breaks with snapping movement leaving the daughter cells connected by a hinge of old cell wall material. So, this type of reproduction in prokaryotes results in a palisade arrangement of the cells.
    Hence, the correct answer is option (c) snapping division.
  • An endospore is a specialized structure produced by certain bacteria during harsh environmental conditions and enables bacteria to live for extended periods. During unfavorable conditions, a bacterium starts the formation of endospore. Hence, the option (b) is incorrect.
  • Binary fission, a kind of asexual reproduction normally takes place in prokaryotes. During binary fission, the bacterial DNA replicates and the parent cells is divided into two identical daughter cells. Hence, the option (d) is incorrect.
  • Pleomorphism is the existence of variant forms in some bacterial species in response to environmental conditions. However the pleomorphic division is not seen bacteria. Hence, the option (a) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 1MTF
All prokaryotes do not reproduce sexually, but reproduce asexually.
The most common type of reproduction carried by the prokaryotes is binary fission. It is often called prokaryotic fission. In this, the DNA (deoxyribonucleic acid) of the bacteria replicates and is pulled to the separate poles. During this process, the bacterium grows in size and starts splitting into two daughter cells. Thus, new cells arise from the pre-existing cells without any kind of sexual reproduction.
Hence, the statement “all prokaryotes reproduce sexually” is false.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 1SA
Bergey’s manual of systemic bacteriology is most authoritative reference in modern prokaryotic classification. Following are several criteria for grouping and classifying bacteria

  • Morphological information about cells like staining and microscopic information, colonial characteristics which cannot identify more specific level than class.
  • Physiological and biochemical information like metabolism of foods and byproducts produced.
  • Serological testing- antibodies identify specific surface antigens.
  • G-C content(guanine and cytosine)- good for clarifying taxonomic positions of groups (more closely related groups have more similar G-C content which is not sensitive enough for species identification.
  • DNA probes.
  • R-rna analysis which have 12 distinct branches.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 2CT
In presence of water and anaerobic conditions iron undergoes corrosion:
Explanation
Iron oxide (rust) forms when iron is exposed to oxygen, particularly in the presence of water. Nevertheless, iron pipes typically corrode more quickly when they are buried in moist anaerobic soil than when they are buried in soil containing oxygen. This is because moist soil contains more amounts of oxygen for corrosion.
Additionally, microorganisms have the capability to form solid surface, which undergoes colonization and proliferate to form biofilms. The phenomenon of corrosion is more when metal iron is exposing to water, due to rapid proliferation.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 2M
Veillonella:
Explanation
Veillonella belongs to genus of anaerobic cocci that live as a part of biofilm (plaque). The bacterium is gram negative and has the ability for lactose fermentation. Moreover, they exist as dental plaque and forms on the teeth of warm-blooded animals. The bacteria exist in the oral mucosa and intestine of mammals.
The process of fermentation done by the bacteria is as follows:
Lactate → acetate + 2 propionate + CO2 + H2O
Thus, the bacterium, “Veillonella”, matches with the term, “dental biofilm”.
Hence, the correct option is (B) dental biofilm (plaque).

Microbiology with Diseases by Taxonomy Chapter 11 Answers 2MC
Some filamentous cyanobacteria like Nostoc punctiforme, Anabaena, can withstand nitrogen starvation with the help of heterocysts. These are specialized nitrogen fixing cells. They fix atmospheric nitrogen using the enzyme nitrogenase. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 2MTF
A Vibrio is the bacterium that is slightly curved in shape, but not the bacterium Bacillus.
The Bacillus is a complete rod shaped bacterium. It is a gram-positive bacterium and it belongs to the phylum Firmicutes. The species of the Bacillus includes two types of species. They are free living species and pathogenic species.
Vibrio is gram-negative bacteria and is curved rod shaped or comma shaped. They are facultative anaerobes. They are mostly found in salt water. They are known to cause most of the foodborne diseases.
Hence, the statement “a Bacillus is the bacterium, which has slightly curved rod shape” is false.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 2SA
Extremophiles are the microbes which require extreme conditions of temperature, PH and salinity to survive. These include thermophiles and halophiles which are major prominent classes.
Thermophiles:
these are prokaryotes whose DNA, RNA, cytoplasmic membranes and proteins do not function properly at temperatures lower than 450C.
Example: Geogemma and Pyrodictium.
The geogemma genera live in hot acidic springs like terrestrial volcanic rifts. The pyrodictum live in deep-sea hydrothermal vents. Biological workers used the enzymes of thermophiles in recombinant DNA technology and also used in several industrial applications.
Halophiles:
these inhabit extremely saline habitats like Dead Sea, Great Salt Lake and solar evaporation ponds. They live in 9 percent Nacl concentration to maintain their cell wall integrity.
Example: Halobacterium.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 3CT
Axial filaments are absent in Gram-positive species:
Explanation
Spirochetes are Gram negative bacteria, having axial filaments, which are motile spiral bacteria. Axial filaments are special types of flagella that wraps around the bacteria between its cell membrane and outer membrane. The type of filaments associated is only with spiral shaped bacteria called spirochetes, which are gram negative. Thus, Gram-positive species don’t have axial filaments.
The flagella are located outside of the cell, which allow the bacteria to move through various types of environments. In contrast, spirochetes allow the movement through viscous medium. This type of motility allows the bacteria to move, regardless of its location. By utilizing ATP (adenosine triphosphate), the flagella are able to beat and propel the cell.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 3M
Clostridium perfringens
Explanation
Clostridium perfringens is an anaerobic, spore forming rod shaped bacteria that exist in soil and sewage. Moreover, less number of cells is found in intestines of humans. Often food poisoning by perfringens results, due to consumption of foods contaminated with Clostridium perfringens more than 108 cells.
Additionally, C. perfringens grows rapidly in meat cooked in bulk where heat penetration is low. Under anaerobic conditions, the spores germinate in sealed cans and jars. Thus, Clostridium perfringens is a pathogenic bacterium that causes gangrene. Gangrene is a serious condition where it can cause myonecrosis, gas production, and sepsis.
Thus, the bacterium, “Clostridium perfringens”, matches with the term, “gangrene”.
Hence the correct option is (C) gangrene.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 3MC
Spirochaete is the term used to describe bacteria having long, spiral or highly coiled shape. This term is applied to any organism that belongs to the order Spirochaetales.
Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 3MTF
Yes, if you were to view Staphylococci, you should expect to see cluster of cells. Staphylococci refer to clusters. They appear round in shape and look like bunches of grapes under microscope. They are gram positive bacteria. Most of them are harmless and usually found on the surface of the skin.
Hence, the statement “if you were to view Staphylococci, you should expect to see cluster of cells” is true.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 3SA
Cyanobacteria:
These are blue green bacteria which vary in size, shape and method of reproduction. They range from 1µm to10µm in diameter. These are small motile filaments which glide away parental strands. Cyanobacteria have gliding capacity due presence of glycol calyx sheath around the body.
Myxobacteria:
These are gram negative bacteria, aerobic, and soil dwelling bacteria which have unique life cycle for prokaryotes. These glides on slime trails, digests yeasts and other bacteria.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 4CT
Clostridium is an anaerobic bacterium isolated form exposed skin:
Explanation
Clostridium is a strictly anaerobic bacterium, which dies in presence of oxygen. The obligatory anaerobes can also tolerate traces of oxygen due to the presence of superoxide dismutase enzyme, which acts as an antioxidant when exposed to oxygen. Hence, it can be isolated from the exposed surface of the skin.
Additionally, Clostridium is responsible for cause of death in living tissue. The bacteria invade through the wound, and multiply. The fermentation products are butyric acid, butanol, acetone, ethanol, and carbon dioxide.
Thus, the ability of microorganisms is avoided by, surgical removal of dead tissue, pressure above atmospheric pressure, and oxygen is toxic to bacteria.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 4M
Clostridium botulinum :
Explanation
Clostridium botulinum comes under beneficial microbes, which produce a deadly toxin, but it has been put to use for cosmetic purpose (botox) to remove the facial wrinkles. Additionally, small dose of the toxin is injected to facial muscles, which paralyzes or weakens the muscles and smoothen the skin, lasting for 6 months. High doses can paralyses, by spreading throughout the body and cause respiratory failure.
Thus, the bacterium, “Clostridium botulinum”, matches the term “botox”.
Hence, the correct option is (D) botox.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 4MC
An endospore is a specialized structure produced by certain bacteria during harsh environmental conditions and enables bacteria to live for extended periods. During unfavorable conditions, a bacterium starts the formation of endospore.
Endospores can remain alive for decades; remain alive in boiling water and also in a state of suspended animation. These have durability and potential pathogenicity and have defensive strategy against hostile or unfavorable conditions. Therefore, the options (a), (b), and (c) are correct. Hence, the correct answer is option (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 4MTF
Elementary bodies are stable resting stages that do not metabolize, but will germinate when conditions improve. These bodies consist of RNA (ribonucleic acid) polymerase that is essential for the transcription of host genome. Even some organelles like ribosomes and ribosomal subunits are found in these bodies. All these characters help elementary bodies to remain stable under unfavorable conditions and to germinate when conditions improve.
Hence, the statement “initial bodies are stable resting stages that do not metabolize but will germinate when conditions improve” is false.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 4SA
The low G+C gram positive bacteria are classified within firmicutes phylum. These include three groups:

  • Clostridia:
    The main classes of low G+C bacteria are the clostridia species. These are rod shaped, obligate anaerobes which form endospores. The clostridia species produce different types of toxin molecules, these toxins act on human body causes serious illness. Example: C.botulinum.
  • Mycoplasmas:
    The second classes of low G+C bacteria are mycoplasmas these are facultative or obligate anaerobes. Mycoplasmas are lack of cell wall, but they have thick plasma membrane with antigenic sterol molecules as protecting groups.
  • Other bacilli and cocci:
    These are composed of both bacilli and cocci which are significant in environmental, industrial and health care settings.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 5CT
According to Louis Pasteur “The role of the infinitely small in nature is infinitely large”. This is because bacteria are small organisms, which are useful in many ways in health, industry, and environments.
Some of the roles of microorganisms are listed below:

  • Clostridium botulinum produce boutilinum toxin, which is used for wrinkles removal, as skin treatment.
  • Lactobacillus is used to produce yogurt and pickles. Bacillus and cocci strains are very beneficial in human health and industry.
  • Streptomyces produces important antibiotics, which are useful for human health.
  • Nocardia used in degradation of pollutants and used for environmental purpose.
  • Azospirillum and rhizobium are nitrogen fixers, which are important in agricultural industry.
  • Acetobacter and Gluconobacter are used to synthesize acetic acid. Agrobacterium in genetic recombination studies.
  • Zoogloea is useful in sewage treatment.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 5M
Bacillus licheniformis :
Explanation
Bacillus licheniformis is a gram positive, beneficial species of bacillus, which is found commonly in soil. Moreover it is also present on the feathers of birds like, sparrows and ducks. The bacterium facilitates the synthesis of the antibiotic, Bacitracin. In addition, it interferes with the synthesis of cell wall, RNA transcription, and damage to the cytoplasmic membrane of microorganisms.
Thus, the bacterium, “Bacillus licheniformis”, matches with the term, “bacitracin”.
Hence, the correct option is (L) Bacitracin.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 5MC
Extremophiles are the bacteria, which can live found in terrestrial volcanic habitats. Hence, the option (b) is incorrect.
Cyanobacteria can photosynthesize without having chloroplast, but they certainly contain chlorophyll. Photosynthesis is not possible without chlorophyll. Hence, the option (c) is incorrect.
Deinococcus radiodurans is an extremophilic bacterium, which can withstand more radiation. It also can survive dehydration, cold, vacuum, and acid conditions. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 5MTF
Archaea are classified into phyla based primarily on rRNA sequences, but not based on tRNA sequences. They were classified as a different group of prokaryotes in 1977 based on the sequences of rRNA genes. There are primarily two groups; archaebacteria and eubacteria. The rRNA sequences are widely used to bring out evolutionary relationships among different organisms, as they are found in all organisms from very primitive organism to very advanced organisms.
Hence, the statement “Archaea are classified into phyla based primarily on tRNA sequences” is false.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 5SA
microbiology-with-diseases-by-taxonomy-chapter-11-answers-5sa

Microbiology with Diseases by Taxonomy Chapter 11 Answers 6CT
Difference between bacterial endospore and actinomycetes spores:
Explanation
Bacterial endospore is a dormant structure, which is very tough and non- reproducing in nature. Moreover, endospore can survive without nutrients and resistant to radiations, desiccation, and high temperatures. Moreover, endospore is formed during unfavorable conditions like shortage of nutrition. The tough coating of endospore is resistant to all unfavorable conditions. When favorable conditions arrive endospore reactivates.
Additionally, bacterial endospore is a vegetative cell that transforms into one endospore, which then germinates to form single vegetative cell. The difference between the bacterial endospores is not reproductive structures like actinomycete spores that are reproductive structures.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 6M
Streptococcus :
Explanation
Streptococcus is a gram positive cocci associated in chains. Staphylococcal burnt skin syndrome is also called bullous impetigo or Ritter’s disease. Moreover, it is a skin infection seen in small children. The toxins produced by Staphylococcus are mainly responsible for the cause of this syndrome.
Similarly, toxin B produced by Staphylococcus is scalded skin syndrome. Toxin B travels through blood to all parts of the body causing scalded skin syndrome. The sores caused by toxin are big and filled with liquid. When the sores break and liquid leaks out then disposing of skin in layers is observed. Skin is stripped off in the form of layers. They cause diseases like pharyngitis, scarlet fever, impetigo, pneumonia etc.
Thus, the bacterium, “Streptococcus”, matches with the term, “impetigo”.
Hence, the correct option is (K) impetigo.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 6MC
Spirilla are any of various bacteria that belong to the genus of gram-negative bacteria. They have elongated spiral form with tuft of flagella. Spirilla cannot fix nitrogen. Hence, the option (b) is incorrect.
Bacteroids is a genus of bacteria that belong to gram-negative bacilli. These bacteria are anaerobic, non-endospore forming. Bacteroids prefer mutualistic relationships. They cannot fix nitrogen. Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 6MTF
Yes, Halophiles inhabit extremely saline habitats such as the Great Salt Lake. Halophiles generally depend on high concentration of salt to keep their cell walls intact and they are salt-loving organism. They stood as an example for extremophile as they love high salt containing environments.
Hence, the statement “Halophiles inhabits extremely saline habitats such as the Great Salt Lake” is true.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 6SA
The arrangement of bacterial cells mainly depends upon two aspects. They are shape of bacteria, and plane of division.
Cocci are the spherical shaped bacteria and bacilli are the rod shaped bacteria. Cocci divide along different planes but bacilli divide along a single plane.
The division of cocci appears in different planes because of its spherical shape. The divided cocci remains attached to each other forms a cluster of organisms namely tetrads, sarcinea, and staphylococci.
The bacilli are divided in single plane hence divided bacilli are attached side by side from long chains namely diplobacilli, streptobacilli, and palisade arrangement. So, the arrangements for cocci are more when compared with bacilli.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 7M
Streptomyces :
Streptomyces are gram-positive bacteria, which belong to the genus of Actinobacteria. The name Streptomyces has been derived, due to the synthesis of antibiotic streptomycin. Moreover, the microorganisms exist predominantly in decaying vegetation and soil. The microorganisms produce useful synthesizing antibiotics like chloramphenicol and neomycin from natural origin. They produce several antimicrobial drugs like tetracycline, Chloramphenicol, and erythromycin. Tetracycline interferes with protein synthesis of microbes.
Thus, the bacterium, “Streptomyces”, matches with the term, “tetracycline”.
Hence, the correct option is (H) tetracycline.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 7MC
Bacteroids are obligatory anaerobic rods that inhabit the digestive tracts of humans. These digest cellulose that is indigestible by mammals. They can cause abdominal, pelvic, blood and other infections so they are the most common anaerobic human pathogens. Hence, the correct answer is option (a) Bacteroids.
Spirochaetes are a group of long, spiral shaped bacteria, some of which are mostly pathogenic to humans. They include the genera Spirochaeta, Borrelia, Treponema, and Leptospira. Hence, the option (b) is incorrect.
Chlamydia is a genus of bacteria that are obligate intracellular pathogens. They are gram-negative, aerobic bacteria. The infections caused by chlamydia pathogens are most commonly found sexually transmitted disease in humans. Hence, the option (c) is incorrect.
Methanopyrus is bacteria that belong to the genus methanogens. They are hyperthermophiles. Methanogens are non-pathogenic to humans. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 7MTF
Yes, the pigments located in thylakoids in phototrophic bacteria trap light energy for metabolic process. These bacteria trap light energy with photosynthetic lamellae. The membranes of thylakoids embed photosystems in it and help the cells to carry photosynthesis. Those photosystems and the pigments present in their membranes are used to trap energy from sunlight, in order to use it for various metabolic processes, including photosynthesis.
Hence, the statement “pigments located in thylakoids in phototrophic bacteria trap light energy for metabolic process” is true.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 7SA
Agrobacterium is an alphaproteobacterium which infects plants to form tumors called as galls. This bacterium inserts a plasmid called Ti which carries a gene for plant growth hormone into the chromosome of the plant. This growth hormone causes the cells of the plant to proliferate into a gall and in turn produce nutrients for the bacterium. So, scientists have discovered that they can insert any DNA sequence into the plasmid making it an ideal vector for genetic manipulation of plants.
The Ti plasmids present on bacterium have variety of genes they include:

  • Origin of replication this sequence helps for replication of the plasmid to increase its copy number.
  • The antibiotic resistance genes help for the selection of the gene inserted copies. The “vir gene” region produce virulence proteins can cause crown gall disease.
  • Ti plasmid contains T-DNA region at this site we can insert foreign (or) required DNA sequences.
    Hence, by this way Agrobacterium is used in Recombinant DNA technology.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 8M
Corynebacterium diptheriae :
Diphtheria is caused by Corynebacterium diphtheria, which is an airborne pathogen. The pathogen is spread from infected to susceptible individuals through coughing, sneezing, and talking. The pathogen infects the tissues of the throat and tonsils. Diphtheria toxin released by the pathogenic strain inhibits protein synthesis, leading to cell death. Extensive tissue destruction causes damage to heart, kidneys, and liver. Death occurs due to suffocation. It is characterized by stones of phosphates within inclusions called metachromatic granules.
Thus, the term bacterium, Corynebacterium diphtheria, matches with the term, “diphtheria”.
Hence, the correct option is (Q) diphtheria.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 8MC

  • Spirochetes belong to the phylum of double membrane bacteria. They are long flexible spiral shaped bacteria. Spirochetes contain axial filaments this characteristic distinguishes it from other bacterial species. Hence, the correct option is (b) spirochetes.
  • Spirillum is the spiral shaped bacterium that belongs to the genus of Gram-negative bacteria. However, this bacterium is not flexible like spirochetes. Hence, the option (a) is incorrect.
  • Vibrio is the bacteria that resemble curved rod shape, belongs to the genus Gram-negative. Hence, the option (c) is incorrect.
  • Rickettsia are pleomorphic non-motile, Gram-negative bacteria. They are obligate intracellular parasites. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 8MTF
Yes, most cyanobacteria form heterocysts in which nitrogen fixation occurs. These bacteria reduce nitrogen and ammonia by a process called nitrogen fixation. Many of these bacteria fix nitrogen in thick-walled cells called heterocysts.
The heterocysts are specialized for fixing nitrogen during the conditions like starvation. Other than cyanobacteria, they are observed in different bacteria like Nostoc punctiforme, Anabaena sphaerica, and Cylindrospermum stagnale.
Hence, the statement “most cyanobacteria form heterocysts in which nitrogen fixation occurs” is true.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 8SA
Proteobacteria phylum is a very large group of gram-negative bacteria which is divided into five classes:

  1. Alphaproteobacteria:
    These include variety of aerobes, capable of growing at low nutrient concentration. Most purple nonsulfur phototrophs are alphaproteobacteria. Some, members of the alphaproteobacteria are nitrifying bacteria.
  2. Betaproteobacteria:
    These include nitrifying Nitrosomonas and pathogenic species like Neisseria(gonorrhea), Bordetella(whooping cough)
  3. Gammaproteobacteria:
    These constitute the largest class of Proteobacteria. These include purple sulfur bacteria, intracellular pathogens, facultative anaerobes that utilize glycolysis and the pentose phosphate pathway and pseudomonas.
  4. Deltaproteobacteria:
    These include Desulfovibrio which are important in the sulfur cycle and in corrosion of pipes. Bdellovibrio which is pathogenic to bacteria and Myxobacteria.
  5. Epsilonproteobacteria:
    These include some important human pathogens like campylobacter and Helicobacter.

These are distinguished by small differences in their r RNA sequences.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 9M
Gluconobacter :
Explanation
Gluconobacter is oval shaped bacteria and is gram negative. It belongs to alphaproteobacteria, which has the ability undergo fermentation in oxidizing alcohols and carbohydrates. Moreover, they can be used in vitamin C synthesis. The size of the genome is very small that is important in industry and environment. It is beneficial and useful in the synthesizes acetic acid (vinegar)
Thus, the term, “Gluconobacter”, matches with the term, “vinegar”.
Hence, the correct option is (I) vinegar.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 9MC

  • Nitrogen fixers are called as alphaproteobacteria, which grow in association with the roots of plants where they convert atmospheric nitrogen to ammonia and make it available for plants as fixed nitrogen. Nitrifying bacteria derive electrons from the oxidation of nitrogenous compounds.Nitrification is the conversion of ammonia and ammonium to nitrate. Hence the correct answer is option (c) nitrogen fixers.
  • Bacteria of the genus Nitrosomonas and Nitrobacter convert ammonia or ammonium to nitrate or nitrite to nitrate. Since they cannot convert nitrogen gas into ammonia, option (a) is incorrect.
  • Nitrogenous is the term used to indicate compounds that contain nitrogen. Bacteria that convert nitrogen gas into ammonia are nitrogen fixers, but not nitrogenous bacteria. Hence, the option (b) is incorrect.
  • Nitrification is the biological process by which ammonia is oxidized into ammonium, then into nitrite followed by the oxidation of nitrites to nitrates. Members of the genera Nitrosomonas and Nitrobacter performs this process as a part of nitrogen cycle. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 9MTF
No, a giant bacterium that is large enough to be seen without a microscope is Epulopiscium, but not Veillonella. Epulopiscium belongs to clostridia, which can be visible without a microscope. Veillonella is a genus of anaerobic cocci that live as part of biofilm (plaque) that forms on the teeth of warm-blooded animals.
Hence, the statement “a giant bacterium that is large enough to be seen without a microscope is veillonella” is false.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 9SA
Cyanobacteria are gram negative phototrophs. They range in size from 1µm to 10µm in diameter. They are true prokaryotic organisms, but they use chlorophyll-a in photosynthesis process like higher plants and algae. Some cyanobacteria species are motile move along the surfaces by gliding process. They commonly reproduce by binary fission, some species from thick walled akinete spores.
The name of blue green algae is changed into cyanobacteria due to color of the bacteria, because of their photosynthetic nature.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 10M
Borditella :
Explanation
Borditella is a pathogenic betaproteobacteria, which causes pertussis or whooping cough.
When the proteins obtained from the bacterium Bordetella pertussis is administered as a part of DTaP vaccine to children after birth. Moreover, it is also administered to adolescents, adults, and healthcare workers in the form of vaccines. Moreover, drugs such as ampicillin, tetracycline, and erythromycin kill the pathogen and prevent drug resistance strains.
Thus, the bacterium, “Borditella”, matches with the term, “pertussis”.
Hence, the correct option is (N) pertussis.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 10MC
Mycobacterium contains mycolic acid in their cell walls. They grow very slowly because they take much time and energy required to enrich their cell walls with high concentrations of long carbon-chain waxes and make the cells resistant to desiccation.Hence the correct option is (D) Mycobacterium.
Corynebacterium belongs to the genus of gram-positive, bacilli. Their distinctive cell wall predominantly contains meso-diaminopimelic acid any many repetitions of arabinogalactan and corynemycolic acid. There is no presence of mycolic acid in the cell walls of Corynebacterium.Hence, the option (a) is incorrect.
Listeria species are gram-positive, rod-shaped bacteria. The cell walls of these species contain ipoteichoic acids, in which glycolipid moiety is covalently linked to the terminal phosphomonoester of the teichoic acid. Mycolic acid is absent in Listeria. Hence, the option (b) is incorrect.
Nocardia belongs to the genus of gram-positive bacilli, which are catalase-positive. They are soil and water dwelling aerobes, sometimes resemble fungi. Only some of the species of Nocardia are partially acid fast due to the presence of intermediate length mycolic acid in their cell walls. Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 10MTF
Yes, when environmental nutrients are depleted, myxobacteria aggregate in mounds to form fruiting bodies.
The myxobacteria are commonly called slime bacteria. They live in soil and feed insoluble organic matter. These divide by binary fission when nutrients are plentiful. But, whenever the nutrients are depleted, these bacteria aggregate as mounds and form fruiting bodies. Hence, the statement “when environmental nutrients are depleted, myxobacteria aggregates in mounds to form fruiting bodies” is true.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 10SA
Difference of nitrification and nitrogen fixation:
Explanation
Nitrification:
It is the process by which bacteria convert reduced nitrogen compounds such as ammonia into nitrate, which is more available to plants. For instance, the process facilitates the removal of nitrogen, by microbes to perform oxidation.
Nitrogen-fixation:
This process is involved in the conversion of atmospheric nitrogen into ammonia. For instance, the relationship leguminous plants and the nitrogen fixing bacteria is important. Since, the gaseous nitrogen present is converted into nitrates, which are usable by plants. Nitrogen is an active major participant of protein synthesis.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 11M
Zoogloea is a betaproteobacteria mainly used for sewage treatment.
Explanation
Zoogloea is aerobic, gram negative bacteria. They are chemoorganotrophic rod shaped bacteria. The bacteria are known for cell aggregates that are embedded in gelatinous matrices. In addition, they contain nitrogenous compounds and polysaccharides belonging to Betaproteobacteria. The bacteria exist in polluted water, mainly involved in sewage water treatment to form floc.
Thus, the bacterium, “Zoogloea”, matches with the term, “floc formation”.
Hence, the correct option is (P) floc formation.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 12M
Azotobacter is mainly used for nitrogen fixation.
Explanation
The genus Azotobacter is ovoid bacteria, which are egg-shaped. They are pseudomonads, soil-dwelling non-pathogenic nitrogen fixers. Moreover, they can be motile by using peritichous flagella, which surrounds them entirely. Their cells are variable and can be rod like or coccoid shaped. They are aerobic and can perform nitrogen fixation.
Thus, the bacterium, “Azotobacter”, matches with the term, “nitrogen fixation”.
Hence, the correct option is (O) nitrogen fixation.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 13M
Desulfovibrio:
Explanation
Desulfovibrio is an obligate anaerobe belongs to anaerobic group of Deltaproteobacteria. They use organic compounds or H2 as electron donor to carry out anaerobic respiration process. Moreover, they are sulfate reducing bacteria, which reduces sulfate (SO42-) to hydrogen sulfide (H2S).
Desulfovibrio, comes under the physiological group that does not have the ability to oxidize acetate and other fatty acid completely. The organisms use pyruvate, lactate, ethanol, and few fatty acids as electron donors. Thus, Desulfovibrio usually found in anoxic environment where there is presence of substrate to reduce. The process of microbial decomposition can make the habitat anoxic.
Thus, the bacterium, “Desulfovibrio”, matches with the term, “iron pipe corrosion”.
Hence, the correct option is (M) Desulfovibrio.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 14M
Chlamydia:
Explanation
Chlamydia is the genus for chlamydias, which are gram-negative cocci that grow and reproduce within the cells of mammals, birds, and few vertebrates. Chlamydia is caused by bacteria like Chlamydia trachomatis. They generally cause a sexually transmitted disease called lymphogranuloma venereum, which is the most common disease in the United States. Moreover, Chlamydia remains untreated in women. The infections show few outward signs because the diseases are asymptomatic. The infections of the lower reproductive tract are usually mild or asymptomatic, especially in women.
Thus, the bacterium, “chlamydia”, matches with the term, “lymphogranuloma venereum”.
Hence, the correct option is (F) lymphogranuloma venereum.

Microbiology with Diseases by Taxonomy Chapter 11 Answers 15M
Cytophaga:
Explanation
The class Cytophaga is slender, rod, and often has pointed ends. The class Cytophaga can actively degrade polysaccharides and play an important role in mineralization of organic matter.
Cytophaga are bacteriods of aquatic gliding rod-shaped aerobes with pointed ends. These bacteria can degrade complex polysaccharides like cellulose, agar, pectin, and chitin to cause damage to wooden boats and degrades raw sewage. Hence, the correct option is (A) wood damage.

Microbiology with Diseases by Taxonomy Chapter 10 Answers

Microbiology with Diseases by Taxonomy Chapter 10 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 10 Answers 1CM
The following concept map can be generated when describing antimicrobial resistance:
microbiology-with-diseases-by-taxonomy-chapter-10-answers-1cm

Microbiology with Diseases by Taxonomy Chapter 10 Answers 1CT
Cocktail is a combination of several antiviral drugs, which are used to treat AIDS (acquired immune deficiency syndrome) and are more effective than using a single agent. This is because the HIV (human immune deficiency virus) will mutate or change a lot. So, using single drug can be effective against one mutation. By using cocktail of drugs it is easy to attack the virus at different points in the life cycle of virus and the patient compliance in taking the medicine is improved.
There are different sites of inhibition like:

  • Inhibition at viral fusion into the cell.
  • Reverse transcriptase enzyme inhibition.
  • Protease enzyme inhibition.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 1L
Aminoglycosides: are amino modified sugars that changes shape of 30S sub-unit causing incorrect pairing of transfer Ribonucleic acid or tRNA anticodons with messenger Ribonucleic acid or m RNA codons. Hence, the correct answer is Aminoglycosides.
Antisense nucleic acids: blocks ribosome attachment to messenger Ribonucleic acid or mRNA.
Hence, the correct answer is Antisense nucleic acids.
Chloramphenicol: blocks enzymatic activity of the 50S subunit and preventing the formation of peptide bonds between amino acids. Hence, the correct answer is Chloramphenicol.
Lincosamides or macrolides: they bind to 50S subunit and blocking proper m RNA movement through ribosome. Hence, the correct answer is Lincosamides or macrolides.
Tetracycline: It is an antibiotic produced from a genus of actinobacteria, known as streptomyces. It block docking site of transfer Ribonucleic acid or tRNA. Hence, the final answer is Tetracycline.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 1MC

  • For the effective treatment of diseases that are infectious. The physicians must be familiar with the specificity of effectiveness, about the pathogen. To access the microbial efficacy variety of test are included, like diffusion test. Hence, the option (a) is incorrect.
  • Dilation susceptibility test includes Kirby-Bauer test. The test reveals the action of effectiveness of most of the drugs towards the particular pathogen. Moreover, the zone of inhibition is greater than the drug-soaked disk of petri plate. The effectiveness of the drug is known. Hence, the option (b) is correct.
  • When drug act on number of pathogens of different types, it is said to be spectrum of action. Moreover, drugs acting on specific kinds of pathogens that are causing disease are called narrow-specific drugs. In addition, drugs that are effective to various kinds of pathogens are called as broad-spectrum drugs. Hence, the option (c) is correct.
  • Diffusion and dilution tests that expose pathogens to antimicrobials are designed to determine, which drug is most effective and determines the amount of drug to use against particular pathogens. Hence, the correct option is (d) both (b) and (c).

Microbiology with Diseases by Taxonomy Chapter 10 Answers 1SA
The important characteristics of ideal chemotherapeutic agent are:
Explanation
An ideal chemotherapeutic agent is readily available, inexpensive, non-toxic, and non-allergenic. Moreover, they are chemically stable and selectively toxic against pathogens. No drug has all these qualities.
There are generally 5 ways, which chemotherapeutic agents damage or kill bacterial pathogens. They include cell wall synthesis inhibition, protein synthesis inhibition, nucleic acid synthesis inhibition, cell membrane disruption, and inhibit metabolites produced in the bacteria.
The following ways are shown how chemotherapeutic agent disrupts pathogen:

  1. Antibiotics inhibit the synthesis of bacterial cell walls. Those structures are thought to interfere with the bacterial enzyme that catalyzes the transpeptidation reaction, which forms peptidoglycan links in the cell wall.
  2. Antibiotics stop protein synthesis by binding to bacterial ribosome, as well as other components of protein synthesis. Thus, halts the processes like transcription or translation.
  3. Antibiotics inhibit synthesis of nucleic acids in two ways. One way is inhibiting DNA polymerase and DNA helicase, which halts replication. Another way is inhibiting RNA polymerase to stop transcription
  4. Antibiotics interfere with bacteria’s cell membrane by binding to the cell membrane to disrupt the structure and permeable capabilities.
  5. Antibiotics block the metabolic processes of bacteria antimetabolites. They interfere with the processes by acting as a strong competitive inhibitor to various enzymes.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 2CT
Penicillium is a mold belongs to fungus. Penicillin secreted by the Penicillium acts against bacterial cell wall and toxic to the bacteria, but not to fungus. The cell wall of bacteria is made up of peptidoglycan; penicillin blocks the formation of peptidoglycan. Fungus is a eukaryote and doesn’t contain peptidoglycan. So, penicillin cannot act against Penicillium. By this way Penicillium escapes the effects of penicillin it secretes.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 2MC

  • For the effective treatment of diseases that are infectious. The physicians must be familiar with the specificity of effectiveness, about the pathogen. To access the microbial efficacy variety of test are included, like diffusion test. In Kirby-Bauer susceptibility test, the presence of a zone of inhibition around disks containing antimicrobial agents indicates that the microbe does not grow in the presence of the agents. Zone of inhibition is greater and the drug is effective. So, the Kirby-Bauer susceptibility test does not depend upon the microbe that grows well in the presence of agents, smallest amount of the agent that inhibit microbe growth, and minimal amount of an agent. Hence, option ‘b’, ‘c’, and ‘d’ is incorrect.
  • Dilation susceptibility test includes Kirby-Bauer test. The test reveals the action of effectiveness of most of the drugs towards the particular pathogen. Moreover, the zone of inhibition is greater than the drug-soaked disk of petri plate. The effectiveness of the drug is known. Zone of inhibition is a clear region where bacteria do not grow. It is measured as the diameter of the clear region, if larger the zone of inhibition, the more effective the drug is. Hence, the correct option is (a) that the microbe does not grow in the presence of the agents.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 2SA
Difference between narrow spectrum and broad spectrum drugs:
Explanation
When drug act on number of pathogens of different types, it is said to be spectrum of action. Moreover, drugs acting on specific kinds of pathogens that are causing disease are called narrow-specific drugs. In addition, drugs that are effective to various kinds of pathogens are called as broad-spectrum drugs. For the effective treatment of diseases that are infectious. The physicians must be familiar with the specificity of effectiveness, about the pathogen. To access the microbial efficacy variety of test are included, like diffusion test.
Narrow spectrum:  The drugs works against few kinds of pathogens, but not to all pathogens.
For example, polymyxin act against gram negative bacteria and penicillin can act only on gram positive bacteria.
Broad spectrum:  The drugs work against different kinds of pathogens.
For example, tetracycline acts against gram negative and gram positive bacteria.
Hence, broad spectrum antibiotics are more effective when compared with narrow spectrum antibiotics. It is not desirable to use the drugs regularly because these may cause secondary infections.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 3CT
Bacillus licheniformis secretes bacitracin, which is an antimicrobial agent that inhibits cell wall formation. Bacillus licheniformis escapes the effects of its own bacitracin because they are resistant to it. This resistance prevents entry of bacitracin into the cell. Those bacteria which lack alanine-alanine cross-bridges are naturally resistant to this drug.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 3MC

  • For the effective treatment of diseases that are infectious. The physicians must be familiar with the specificity of effectiveness, about the pathogen. To access the microbial efficacy variety of test are included, like diffusion test. Hence, the option (b) is incorrect.
  • The effectiveness of the drug is known. Zone of inhibition is a clear region where bacteria do not grow. It is measured as the diameter of the clear region, if larger the zone of inhibition, the more effective the drug is. Hence, the option (c) is incorrect.
  • When drug act on number of pathogens of different types, it is said to be spectrum of action. Moreover, drugs acting on specific kinds of pathogens that are causing disease are called narrow-specific drugs. In addition, drugs that are effective to various kinds of pathogens are called as broad-spectrum drugs. Hence, the option (d) is correct.
  • Selective toxicity refers to the ability of a chemotherapeutic agent to inhibit or kill a pathogen, while causing little or no harm to the host. It is expressed in two terms:
    • Therapeutic dose or the amount of drug to treat a disease.
    • The amount of drug in which it becomes toxic for the host.
  • The key to successful chemotherapy is selective toxicity against microbes and harmless to humans.
    Hence, the correct option is (a) selective toxicity.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 3SA
Drug Z destroys NAM part of cell structure:
Explanation
Peptidoglycan is a complex compound that is a key component of the cell wall of bacteria. It is is made up of long sugar (glycan) groups that are attached to amino acid chains. These glycan chains are made of N-acetylmuraumic acid (NAM) and N-acetylglucosamine (NAG). The amino acid chains are covalently cross-linked to one another creating a layered structure of amino acids and sugars; hence, the name peptidoglycan. Peptidoglycan provides the structural support, for the cell wall.
Similarly, NAM is a component of bacterial cell wall, which is absent in human cell membrane. So, drug Z targets only NAM, which is present in bacteria and can be used in chemotherapy.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 4CT
Despite wide variety of known antibiotics less than 1% of drugs have practical value in treating the diseases. This is because the morphological characters for prokaryotes are similar and the drug targets for most of the antimicrobials are same. So, these drugs have both medical and commercial value in treating the variety of diseases.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 4MC

  • Sulfonamides drugs are produced first produced in the form of dye. They are analogs of PABA, which are capable of binding to the enzyme irreversibly by forming dihydrofolic acid. They are specific to spectrum of action and effective against the bacteria, protozoa, and fungi; however the importance of the drugs is widespread. Hence, the option (a) is incorrect.
  • Sulfonamides are effective because humans and microbes use folic acid and PABA differently in their metabolism. Sulfonamide is a structural analog of para-aminobenzoic acid, which is needed for nucleic acid synthesis in bacteria. Hence, the option (d) is incorrect.
  • Sulfonamides are analogs in structure to PABA, which differs from humans. Thus, the drugs prevent the amino acids incorporation into polypeptide chains. Hence, the option (b) is incorrect.
  • In humans PABA (para-amino benzoic acid) is not essential and folate should be taken from diet. So, the metabolic process involved in both human and microbes are different and the targets are different for antimicrobial agent to act.
    Hence, the correct option is (c) humans and microbes use folic acid and PABA differently in their metabolism.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 4SA
Antimicrobial agents target on ribosomal sites of human cells and pathogens:
Explanation
Targets for antimicrobial agents differ in the ribosome subunits for both humans and pathogens. Pathogens have 70S ribosomes with 30S and 50S subunits and humans have 80S ribosomes with 60S and 40S subunits. Antimicrobial agents selectively targets bacterial protein synthesis in different steps. Due to this difference in the ribosomes of humans and pathogens there is no problem in the process of protein synthesis for humans. Moreover, it is safer to use antimicrobial agents even though mitochondria of humans contain 70S ribosomes with fewer side effects.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 5CT
The possible ramifications or complications for usage of antimicrobials against infections caused by the moths and butterflies are development of resistance to the infections. Over usage of such antimicrobials causes toxicity. Ciprofloxacin is generally used by moths and butterflies collectors, which is recommended by Lepidopterists society in 2000.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 5MC
Cross resistance takes place when the resistance to one chemotherapeutic agent confers resistance to similar drugs. Whereas, multiple drug resistant pathogens are resistant to many types of antimicrobial drugs. Thus, cross resistance does not include: the deactivation of an antimicrobial agent by bacterial enzyme, mutation of genes that affect the cell membrane channels, and alteration of resistant cells. Hence, the options (a), (b), and (c) are incorrect.
Cross resistance is defined as resistance that typically occurs when one antimicrobial agent may confer resistance to similar type of drugs. It generally occurs when drugs are similar in their structure. For example, resistance to one aminoglycoside drug like streptomycin can confer resistance to similar aminoglycoside drug. Hence, the correct option is (d) resistance to one antimicrobial agent because of its similarity to another antimicrobial agent.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 5SA
Antimicrobial agents produce resistant cells:
Explanation
Antimicrobial agents induce some enzymes, which can destroy the drugs and make the process slow or prevent the entry of drug. Moreover, it can alter the target of the drug, which can alter in metabolic chemistry, and pump the antimicrobial agent out of the cell before drug can act. Thus, according to these considerations antimicrobial agents produce resistant cell where drugs cannot act further.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 6CT
Gentamicin has wide range of activity against both gram positive and gram negative bacteria. Even though they cause deafness these are used for the treatment of pneumonia and is the better choice of drug to treat this disease. Gentamicin exclusion assay is carried out and the activity of drug against the disease is calculated; and is fixed to be as a better choice of drug for pseudomonas infection.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 6MC

  • Multiple-drug-resistant pathogens are called as superbugs that are resistant to three to more against antimicrobial agents. Thus, multiple-drug-resistant microbes are not resistant to all antimicrobial agents, and do not respond to new antimicrobial agents. Hence, option (a) and (b) are incorrect.
  • Multiple-drug-resistant microbes are resistant to three or more types of antimicrobial agents. Examples include multiple-drug resistant strains of Staphylococcus, Streptococcus, Enterococcus, Pseudomonas, Mycobacterium tuberculosis, and Plasmodium are resistant to two or more different types of antimicrobial agents. They develop resistance generally in hospitals. Hence, the correct option is (c) frequently develop in hospitals.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 6SA
Pathogen resistant strains are related to general development of persons:
Explanation
There are several methods to prevent development of resistance against antimicrobial drugs:

  1. Allow your body to defeat pathogen on their own, so that drug can be maintained in a patient’s body for long time. Moreover, destroys all sensitive cells and inhibit others for the body’s defense to defeat them.
  2. Using combination therapy with other antimicrobial agents. Some drugs enhance the effect of other drug in a process called synergism.
  3. Limit the use of antimicrobials to necessary cases, so that unwanted usage of drugs can be reduced.
  4. Using new generation drugs like second and third generation drugs, which are less resistant.
  5. Using full course of antibiotics.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 7CT
Pregnant and nursing women should not take tetracycline for sore throat infection because tetracycline is a broad spectrum antibiotic used to treat sore throat. It has mutagenic qualities, which can cause damage to the unborn child. It passes into breast milk and cause bone problems and teeth staining in nursing women. It causes a baby to be more sensitive to sunlight and increase the risk of fungal infections. Hence, the decision taken is a poor one.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 7MC
Vancomycin is a chemical compound, which has action on bactericidal agent and capable of killing bacteria. Thus, Vancomycin is an example of bactericidal agents that is capable of disrupting cell wall formation of Gram-positive bacteria. Thus, the option (b) is incorrect.
Bacitracin do not have beta-lactam ring in their structure. Moreover, blocks NAG and NAM transport from cytoplasm. Thus, the option (c) is incorrect.
Isoniazid is the most widely used drug in the treatment of tuberculosis. Its studies have shown that they inhibit a crucial enzyme in tuberculosis bacterium. A covalent adducts is formed between carbonyl of isoniazid and nicotinamide ring of the NAD molecule. Thus, the option (d) is incorrect.
Penicillin generally associates with beta-lactam ring. It is the functional portion of the drug, which shows antimicrobial activity by interfering the disruption of bacterial cell wall. Bacitracin, vancomycin, and isoniazid do not have beta-lactam ring in their structure. Hence, the correct option is (a) penicillin.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 7SA
Antiviral drugs are difficult to develop:
Explanation
Antiviral drugs or medicines will inhibit the lifecycle of virus. These medicines will make the virus less likely to replicate; thus, used to slow down the rate of infection. In addition, they also prevent the influenza virus from leaving the infected cell.
Furthermore, viruses generally utilize host cells enzymes and ribosomes for the metabolism and replication. They are present inside human cells; so, drugs have to penetrate human cells to act against viruses, which are harmful for human cells. Thus, antiviral drugs are difficult to develop as they destroy human cells.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 8CT
Acyclovir has replaced Adenosine arabinoside to treat herpes virus infection because Adenosine arabinoside is fatal to host cells, as they incorporate the drug into cellular DNA (deoxyribonucleic acid). It also causes anemia. Acyclovir is phosphorylated by virally coded kinase enzyme, which activates the drug.
Adenosine arabinoside is phosphorylated by cell-coded kinase enzyme, which activates the drug. Due to these adverse effects shown by adenosine arabinoside it is replaced with acyclovir. Acyclovir is a better choice because it inhibits both DNA and RNA (ribonucleic acid) synthesis and has no adverse effects like adenosine arabinoside.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 8MC
Aminoglycosides acts against protein synthesis. They irreversibly bind to 30S subunit of prokaryotic ribosomes, causing ribosome to mistranslate mRNA and stop the protein synthesis.
Beta-lactams inhibit bacterial cell wall, polymyxin destroys cytoplasmic membranes of susceptible cells, and trimethoprim interferes with the bacterial nucleic acid synthesis. Hence, the correct option is (d) aminoglycosides.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 8SA
Broad-spectrum drugs therapy causing unintended consequences:
Explanation
Broad-spectrum drugs have a wide range of effectiveness; they are effective against a wide array of pathogen types. While some are very effective, the types of drugs tend to have a lower therapeutic index, since they are, so broad and target a wide range of processes to disrupt in a pathogen. Additionally, broad-spectrum antibiotic can act against wide range of bacteria like both gram positive and gram negative bacteria. This may destroy or kill the normal gut flora, which reduces microbial antagonism leading to development of secondary or super infections.
Thus, development of secondary infections is the unintended consequences that can arise from therapy.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 9CT
Amphotericin B is a polyene antifungal drug that is extracted from Streptomyces nodosus. This drug targets renal vasculature and make them constrict to reduce the glomerular filtration rate by more than half. There is an increase in creatinine is observed during the use of amphotericin B. So, it affects mainly kidneys rather than other parts in the body.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 9MC
Drugs that neutralize the acidity of phagolysosomes prevent viral coating. Moreover, nucleotide analogs act in deoxyribonucleic acid synthesis like nucleosides. They include antiviral products that can be used to stop viral replication. Thus, drugs containing protease inhibitors retard viral growth by blocking essential viral proteins. Hence, the options (b), (c), and (d) are the correct statements.
Macrolides contains macrocyclic lactone ring. It shows its action by binding to 50S subunit of prokaryotic ribosomes. Moreover, inhibits preventing in elongation of nascent protein. So, the statement macrolide drug that blocks attachment sites on host cell wall prevent viruses from entering, is false statement.
Hence the correct option is (a) macrolide drug that blocks attachment sites on the host cell wall and prevent viruses from entering.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 9SA
Similarities and differences between the following compounds:
Explanation
Polyenes:
The compounds disrupt cytoplasmic membrane in the cells and cause lysis to cells. The compounds associate with the molecules of ergosterol forming a pore through the fungal membrane, which leads to leakage of essential ions from the cells. For instance; Nystatin and Amphotericin B
Azoles:
The compounds inhibit the synthesis of ergosterol and disrupt cytoplasmic membrane. Hence, the cell membrane doesn’t remain intact and fungal cell dies; for instance, fluconazole, and ketoconazole.
Allyamines:
The compounds inhibit the synthesis of ergosterol; for instance, terbinafine.
Polymyxin:
The compounds disrupt lipid bilayer of cytoplasmic membrane in gram negative bacteria and are toxic to humans; for instance, Bacillus and polymyxa.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 10CT
Benzimidazole derivatives have many therapeutic uses including antifungal, antitumor, analgesics, antiviral, antiparasitic and antihistamine etc. These drugs act by inhibiting the microtubule formation and glucose uptake. Microtubules are formed by the polymerization of tubulin proteins. This polymerization is necessary for mitosis. During mitosis chromosome arranged on a metaphase plate are distributed equally to the two cells by the pulling action of microtubules. If the polymerization of microtubules is ceased, then mitosis cannot be completed.
The same microtubules constitutes the flagella, hence blockage of tubulin polymerization results in the dis-functioning or formation of impaired flagella.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 10MC
PABA is para-amino benzoic acid. It is structurally similar to sulfonamides. Moreover, PABA is required in the synthesis of nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) of many organisms. During the process of degradation, most of the organisms convert PABA to dihydrofolic acid to tetrahydrofolic acid and then to folic acid. Folic acid is used as a coenzyme in the synthesis of purines and pyrimidines.
Since, PABA is required in the synthesis of nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) of many organisms. Thus, it is not a substrate used in the production of penicillin; it is not a type of beta lactamase, and its molecular is not similar to cephalosporins
Hence the correct option is (d) used to synthesize folic acid.

Microbiology with Diseases by Taxonomy Chapter 10 Answers 10SA
Difference between antagonists and synergism:
Explanation
Antagonists:
These agents interfere with the other drugs or any attachment of viruses to the host. For example, penicillin’s act only against growing and dividing cells.
Synergism:
These agents enhance the effect of second drug, which is used in combination. For example, penicillin makes streptomycin molecule easier to enter bacteria for protein synthesis.
Drugs are classified as agonists, whereas some other drugs are classified as antagonists;

  1. Sumatripan is sold as Imitrex, which is an effective in treating migraine headaches. It acts as an agonist at the serotonin receptor. The effect of Imitrex prolongs the effect of serotonin.
  2. Ondansetron is sold as Zofran, acts on a subclass of serotonin receptors to inhibit nausea and vomiting. It is frequently prescribed to patients in chemotherapy. It acts as an antagonist at the receptors. The effect of Zofran blocks the response at the receptor.

Microbiology with Diseases by Taxonomy Chapter 9 Answers

Microbiology with Diseases by Taxonomy Chapter 9 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 9 Answers 1CM
microbiology-with-diseases-by-taxonomy-chapter-9-answers-1cm

Microbiology with Diseases by Taxonomy Chapter 9 Answers 1CT
The antimicrobial agents used for longevity of sandwich:
Explanation
Grilled cheese sandwich is a diary product, which attract microorganisms quickly, if necessary precautions are not taken. The supplier had stored the sandwich in an air tight box for ten years without decay or the growth of mold by using antimicrobial chemical.

  1. The chemical agents include nisin and natamycin that reduce the growth of bacteria and fungi in cheese.
  2. The physical agent he used for preservation is ultra high temperature sterilization of moist heat that denatures proteins and destroys membranes of microbes.
  3. Desiccation is also used for preservation and inhibits the metabolism of organisms.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 1MC

  • Sterilization can eliminate harmful microorganisms but hard to eliminate viruses as they do not have protein coat to sterilize.
  • The process of sterilization needs destruction of the protein coat and eventually killing the organism.
    Hence, the option (b) is incorrect.
  • Sterilization cannot eliminate prions as they are one of the viral particles that lack protein coats.
    Hence, the option (c) is incorrect.
  • Sterilization cannot eliminate hyperthermphiles because these organisms can tolerate high temperatures. So, this process cannot work on these organisms. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 1SA
Resistance is the condition where microorganisms remain normal even in the presence of antimicrobial drugs and unfavorable environments. These adverse effects can show no negative effect on those resistant microorganisms.

  1. Some bacterial endospores:
    These are the most resistant forms of life; they can survive in unfavorable conditions for several years. They can survive for more than 20 years in 70% alcohol. Endospores of Bacillus and Clostridium species are resistant forms.
  2. Mycobacterium species:
    These organisms can survive by their waxy cell wall (mycolic acid) in dry conditions and also can survive against most water based chemicals and drugs. The mycolic acids present in their cell walls made them resistant to the adverse condition.
  3. Cysts of some protozoa:
    Protozoan cyst walls prevent the entry of disinfectants and protect them from drying and heat.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 2CT
Antimicrobial effect of desiccation when grapes are dried in sun:
Explanation
Desiccation is a physical method of microbial control, which inhibits metabolism of microbes by killing them. Moreover, desiccation is the only method, which has antimicrobial effect operating when grapes are dried in the sun to make raisins. That is why dried food can be stored longer without any contamination. Sometimes, UV light can also kill microbes and fungi. The sugar, which is present in grapes are stable without any contamination when it is dried.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 2MC

  • Antiseptics are the antimicrobial substances that reduce the effect of infection of living tissues or skin. Hence, the option (a) is incorrect.
  • Degermers are the antigermal substances that kill harmful germs as well as beneficial germs. Hence, the option (c) is incorrect.
  • Pasteurization is a process that is used for heating the food products, which are found in liquid state for a fixed length of time. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 2SA
Phenol coefficient:
It is the oldest method in which efficacy of various disinfectants and antiseptics are evaluated by calculating the ratio of agent’s ability to control microbes to that of phenol under standard conditions. If phenol coefficient is greater than 1, it indicates that the disinfectant is more effective than phenol; and the larger ratio indicates that the disinfectant is more effective.
Kelsey-Sykes capacity test:
It determines the capacity of a given chemical to inhibit bacterial growth. Here bacterial suspension is added to a chemical then the turbidity is observed. If there is lack of turbidity then there is lack of bacterial growth. Turbidity in the medium indicates that bacteria got survived.
In-Use test:
It is a more realistic method for determining efficacy of a chemical, even though it is more time consuming. It checks the real lives situations in which swab from a suspected site are grown on a media and check for growth.
Use-Dilution test:
This test measures efficacy of detergents and antiseptics against specific microbes. In this test, several metal cylinders are dipped into broth culture of bacteria and dried at 37oC. Now each contaminated cylinder is dipped into different dilutions of detergents and antiseptics, later incubated in a sterile medium for 48 hours. The most effective agent is the one that entirely prevents microbial growth at the highest dilution.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 3CT
D value is defined as reduction time in decimal reduction, which is necessary to destroy 90% of microbes in a sample. This value differs with the organism.
The given D value used in the assay of 3 minutes:
100 trillion bacteria (1014) should get reduced to 10 viable cells; so, there should be reduction of 13 folds to produce 10 viable cells from (1014).
Thus, 3×13 gives 39 minutes.
Hence, it takes 39 minutes to reduce a population of 100 trillion bacteria to 10 viable cells.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 3MC

  • Antisepsis is the process to destroy disease causing microorganisms to prevent infection. Hence, the option (b) is incorrect.
  • Sterilization is the process to remove microbial forms like bacteria, fungi, and viruses, and spores. Hence, the option (c) is incorrect.
  • Sanitization process removes pathogens from the objects, places, and utensils used by the public to reduce the number of pathogenic microbes to meet public health standards. These standards vary among governmental jurisdictions. So, sanitization best describes the disinfecting of cafeteria plates. Hence, the correct option is (d) sanitization.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 3SA
Mycobacterium tuberculosis causes tuberculosis. The cell wall of these bacteria comprises of lots of waxy lipids and mycolic acids, which allow bacteria to survive against dry conditions. These waxy lipids and mycolic acids also protects these microorganism from most water based chemicals and drugs. Hence, it is highly essential to use strong disinfectants in areas exposed to tuberculosis patients.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 4CT
Reduction of potential pathogenic bacteria in hospitals:
Explanation
The hospital personnel should follow the sterilization procedures by using disinfectants. Additionally, disinfectants reduce the spread of pathogens and destroy most of the microorganisms and viruses on non living tissues like cotton blends of scrub suits, clothes of nurses, lab coats, computer keyboard etc.
The widely used disinfectants are as follows:

  1. Phenolic.
  2. Alcohols.
  3. Aldehydes.
  4. Soaps.

Thus, using strong disinfectants can destroy pathogenic bacteria and fungi, which include strains of Enterococcus, staphylococcus, candida, and aspergillus.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 4MC
Microbial death is a permanent loss of reproductive capacity of pathogens or microorganisms. The rate of microbial death evaluates the efficacy of an antimicrobial agent, which will not simultaneously kill all cells rather; they kill in a constant percentage of cells over time. This is usually a constant value for a particular microorganism over time and particular set of conditions. So, the rate is used to measure the efficiency of a detergent, an antiseptic and efficiency of sanitization technique.
Hence, the correct option is (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 4SA
Warm disinfectants work better than cool ones, because they have better penetrating power with heat and the chemicals can react faster at higher temperatures. So, they can remove microbes that are present in that area by better penetration due to heat. For example, microbial death rate is high at higher temperatures. If a disinfectant kills same number of microorganisms, it requires 4 minutes at 450C, but 12 minutes at 200C.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 5CT
The following treatments and precautions are taken by growers and consumers:
Explanation
Salmonella enterica causes salmonellosis (severe diarrhea) in US, which is an outbreak. USFDA (US Food and Drug Administration) revels, the food that is contaminated is a component in fresh salsa like raw tomatoes, jalapeno peppers, Serrano peppers. Moreover, Salmonella can enter through broken tomatoes and leaves, so growers and packers should take care while growing and packing. Water should not be contaminated with the bacteria. Consumers should wash the stuff in running water before using or eating. Washing hands also is necessary before eating.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 5MC
An ideal antimicrobial agent should be inexpensive, fast acting and stable during storage. These agents alter the membranes and cell wall and damage nucleic acids and proteins of the animal. These agents act mainly on nucleic acids and produce fatal mutations.
Furthermore, these agents should not be harmful to humans, animals and objects and should control growth and reproduction of all microorganisms.
Hence, the correct option is (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 5SA
Gram-positive bacteria has thick peptidoglycan layer when compared with gram-negative bacteria. Gram-negative has outer lipopolysaccharide, which contains lipids. The lipids can be easily dissolved at higher temperature and they cannot stand as protective covering. So, gram-negative bacteria are more susceptible to heat than gram-positive bacteria. The gram-negative bacteria are not only susceptible to heat, but also to various antibiotics and disinfectants.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 6CT
Medicated over-the-counter foot powder action against fungi:
Explanation
Over-the-counter foot powder is mediated. Moreover, the powder contains the element zinc oxide, which is proven to have antimicrobial activity. Additionally, over-the-counter medicated foot powder contains camphor, eucalyptus oil, lemon oil, and zinc oxide. It also inhibits the growth by affecting cellular functions and causes deformation in fungal hyphae.
Thus, camphor, eucalyptus oil, and lemon oil are considered as inactive ingredients in the preparation.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 6MC

  • Salmonella enterica is a flagellated, gram-negative bacterium. They cause a disease, salmonellosis, which is carried by infected food products. These organisms do not have any biological significance. Hence, the option (b) is incorrect.
  • Mycobacterium tuberculosis is a pathogenic causative agent that causes tuberculosis. These bacterium need oxygen to survive, they cannot live in high extreme temperatures. Thus, they are biologically insignificant. Hence, the option (c) is incorrect.
  • Staphylococcus aureus is a bacterium, which is generally found on the human skin and respiratory tract. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 6SA
There are different methods to control microorganisms. Those methods are classified as physical methods and chemical methods. Some of the physical methods to control microorganism are as follows:

  1. Moist heat:
    This method kills cells by denaturing proteins and destroying cytoplasmic membranes. It is used to sterilize chemicals and to disinfect and sanitize different objects. Example: Disinfecting baby bottles
  2. Dry heat:
    Hot air is used to denature proteins and foster oxidation of metabolic and structural chemicals. It requires high temperatures for longer times than moist heat, because it penetrates more slowly.
  3. Refrigeration and Freezing:
    It halts the growth of most pathogens because chemical reactions occur slower at lower temperatures. It is used in food preparation and storage.
  4. Ionizing radiation:
    It denatures the DNA (deoxyribonucleic acid) molecules, which are mutated and responsible for cell death.
  5. Osmotic pressure:
    It uses high concentrations of salt or sugar in foods to inhibit microbial growth. The removal of water inhibits cellular metabolism because enzymes are fully functional only in aqueous environments. These are used to preserve foods like salted fish.
  6. Desiccation and Lyophilization:
    It is the technique, which combines both freezing and drying. It inhibits metabolism and is used for long term storage of bacterial cells and for preservation of foods.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 7CT
Communicable diseases are common after any natural disaster had occurred. The diseases have increased risk of waterborne illnesses. The disease of water born includes cholera, typhoid, and hepatitis A, E.
The following steps are taken by the people to lessen the spread of waterborne diseases of cholera include:

  1. The primary and healthcare services are to be accessed to bring water safe.
  2. Diseases such as epidemic-prone diseases are detected in the areas affected.
  3. The priority of the communicable disease can be detected for inclusion in the surveillance system. In addition, the need for immunization and vector-control campaigns are arranged.
  4. Antimicrobial drugs stocks of rehydration fluids for vaccines and cholera patients are sent to affected area.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 7MC

  • Phenol coefficient is measurable scale that provides information about the bacterial activity of a chemical compound with respect to phenol. This measurable scale provides information on comparable activity but not the accurate activity of the bacteria. Hence, the option (b) is incorrect.
  • Filter paper test is a test paper that is used to filter bacteria with help of a semi-permeable paper. It can be used by placing perpendicularly to an air or liquid flow. This test is dependent on various other factors to get accurate results. Some of the factors like porosity, wet strength, retention of the particles, compatibility, capacity, flow rate etc. Hence, the option (c) is incorrect.
  • In-use test is performed by the company that manufactures an antimicrobial cleaner for kitchen. It provides an accurate determination of efficacy under real life conditions although it is time consuming process. Hence, the correct option is (d) In-use test.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 7SA
Thermal death point is the lowest temperature that kills all cells in the broth within 10 minutes, whereas thermal death time is the time that it takes to completely sterilize a volume of liquid at a set temperature. It determines the time required by the drug or disinfectant, to completely sterilize the liquid at a particular temperature. In reality, this method was developed for sterilizing canned foods, but they were found to be more useful even for sterilizing pharmaceutical and cosmetic products.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 8CT
Commercial use of antiseptics and disinfectants:
Explanation
Americans are preoccupied with antisepsis and disinfection, as evidenced that every product contains antiseptics and disinfectant chemicals. Moreover, hand soap, shampoo, toothpaste, hand lotion, and deodorants contain antiseptics. Additionally, cutting boards, scrubbing pads, children toys, and laundry detergents also contain disinfectants. So, extensive use of such products adds to human and animal health, but it promotes the development of strains of microbes that are resistant to antimicrobial agents because the susceptible cells die and resistant cells remain to proliferate.
Hence, widespread commercial use of antiseptics and disinfectants has hurt rather than helped American health.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 8MC

  • An incinerator is combustion vessel or chamber, which is used for treating waste materials or products. These vessels cannot serve the purpose of holding pressure for longer periods. Hence, the option (b) is incorrect.
  • A desiccator are sealable enclosures that contain desiccants, which are used to protect or preserve such items that are moist-sensitive. They do not work as autoclaves. Hence, the option (c) is incorrect.
  • A pressure cooker works like an autoclave because it maintains the same temperature and pressure and also it works with the same principle as autoclave works. Steam sterilizes the contents of an autoclave when it is maintained temperature 121 0C and pressure 15 psi for 15 min. Hence, the correct option is (d) a pressure cooker.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 8SA
Pasteurization is a method of heating foods to kill pathogens and control spoilage without altering the quality of food. Pasteurization allows thermophilic and thermoduric bacteria to survive (not pathogenic), but Sterilization eradicates and kills all microbes. So, “Pasteurization is not sterilization.”

Microbiology with Diseases by Taxonomy Chapter 9 Answers 9CT
Quaternary compounds of ammonium are not active against Mycobacterium tuberculosis :
Explanation
Quaternary ammonium compounds or quats are the surfactants, which act by disrupting the cellular membranes so that affected cells lose essential internal ions like potassium ions. They are bactericidal, mostly against gram positive bacteria. In contrast, the agents are not effective against non-enveloped viruses like mycobacterium (Mycobacterium tuberculosis). Thus, contain large amounts of waxy lipids, so it allows the bacteria survive in drying and protect them from most water based chemicals.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 9MC

  • Lyophilization is a dehydration process, which is used to preserve sensitive materials or perishable material. In another terms, it is also known as freeze-drying. This process is used to prepare the perishable material to transport in a convenient way. Hence, the option (b) is incorrect.
  • Beef jerky can be preserved from microbial growth by desiccation or drying. In this process the water in the meat gets removed there by it inhibits the metabolism of microorganisms thereby used for preservation of beef jerky for long time.
    Hence, the correct option is (c) desiccation.
  • Radiation is a process that uses energetic particles or waves to kill organisms. These are harmful to biological systems. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 9SA
Desiccation:
It is the state or condition of extreme drying. It inhibits growth of the microorganism by completely removing the water that microbes need for their metabolism. It is also called drying and is mostly used for preservation of foods. The desiccants are the substances that involve in desiccation and they are hygroscopic in nature.
Lyophilization:
This process is otherwise called freeze-drying or cryodesiccation, as it uses freezing and drying procedures to preserve microbes for many years. This is a long term preservation method among the different microbial culture methods known. Dehydration is the typical principle even in this process.
Differences between Lyophilization and desiccation:

  1. Lyophilization is used to preserve different strains of the microorganisms, while desiccation is used to eradicate microorganisms from an area.
  2. Lyophilization process is used for the cells that are sensitive to heat and contain very delicate structures, whereas desiccation is used against all cells.
  3. Very less or no harm occurs to the microbes in Lyophilization, whereas cells will be harmed greatly in desiccation.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 10MC

  • Visible light waves are those ranges of waves where all objects are visible for a human or animal naked eye. These waves are not harmful and do not have ability to harm organisms. This is not used for antimicrobial technique. Hence, the option (b) is incorrect.
  • Radio waves are lengthy waves that travel longer distances. They do not effect organisms, as they are less intensive to make harm. This is not used for antimicrobial technique. Hence, the option (c) is incorrect.
  • Microwaves are highly intensive infrared rays that can pass through any object. They are highly penetrative and harmful to living organisms, if exposed to external environment. This is not used for antimicrobial technique. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 10SA
Halogens, alcohols, and oxidizing agents are the different agents used for controlling the growth of microorganisms. They have different actions on the microorganisms.

  • Alcohols:
    They denature proteins and disrupt cell membrane. These are intermediate-level of disinfectants. They are also used as antiseptics before injections. The proteins treated with alcohols cannot fold properly and cannot function. As a result, the cells will die.
    Example: Ethyl alcohol
  • Halogens:
    They denature proteins and kill microbes present in water or on medical instruments or skin. These are also intermediate-level of disinfectants.
    Examples: iodine, chlorine, bromine, and fluorine.
  • Oxidizing agents:
    These denature proteins by oxidation. They release oxygen free radicals, which are toxic to microbes and some anaerobes. These are high-level disinfectants.
    Examples: hydrogen peroxide, per-acetic acid, and ozone.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 11MC

  • Phenols are intermediate to low level disinfectants. They can disrupt cell membrane and denature proteins. They are more effective against aerobic microorganisms rather than anaerobic microorganisms. Therefore, the option (a) is incorrect.
  • Silver, which is a heavy metal ion, can act as antimicrobial agent. It has the ability to combine with sulfur atoms present in cysteine molecules, thereby denaturing the proteins. They are more effective against aerobic microorganisms rather than anaerobic microorganisms. Therefore, the option (b) is incorrect.
  • Ethanol has bactericidal, fungicidal, and virucidal properties. They are regarded as intermediate level disinfectants. They are very much effective against aerobic microorganisms, rather than anaerobic microorganisms. Therefore, the option (c) is incorrect. Hence, the correct answer is option (d) hydrogen peroxide.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 11SA
Hyperthermophilic prokaryotes are viable in canned goods after post sterilization:
Explanation
Autotrophically growing green non-sulfur phototroph, utilize H2 (hydrogen) or H2S (hydrogensulphide) as electron donors. The organism carries out hydroxypropionate pathway by reducing two molecules of CO2 to glyoxylate; for instance, Chloroflexus. Hydroxypropionate is a three carbon compound and is vital intermediate in hydroxypropionate pathway. Apart from Chloroflexus many hyperthermophilic archaea like Metalosphaera, Sulfolobus, and Acidianus carry out hydroxypropionate pathway. These are non-phototrophic organisms, which are present near the base of Archaea in the phylogenetic tree. Therefore, hydroxypropionate pathway roots are very deep. Besides, hyperthermophilic prokaryotes survive at high temperatures and environmental conditions like acidity or radiations.
Therefore, hyperthermophilic prokaryotes remain viable in canned goods after commercial sterilization because the microbes grow at 85oC, but not at 37oC where the food is stored. So, this situation doesn’t create any problem to consumers.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 12MC

  • Aseptic means an environment or a procedure, which is free of pathogenic contaminants. Aseptic will best describe a surgical procedure that is free of microbial contamination. Another example is vegetables and fruits packed in aseptic conditions. They are completely free of microorganisms. Therefore, the option (d) is correct.
  • Disinfection is the use of different chemical and physical agents as disinfectants. They include heat, alcohol, ultraviolet light, bleech, etc. They have the ability to inhibit microorganisms, but they cannot ensure that all microbes are destroyed and the surface is free of them. Therefore, the option (a) is incorrect.
  • Sanitization is the process of disinfection in public places like restaurants. The places and utensils that are utilized by large number of people are sanitized rather than disinfected. Even this process of sanitization cannot ensure the complete destruction of microbes. Therefore, the option (b) is incorrect.
  • Degerming is a process of removing microbes by scrubbing. For instance, when we wash our hands we degerm our hands. Similarly, nurses before injecting, they degerm that particular area by scrubbing with cotton and alcohol. Even this process cannot ensure complete destruction of microbes. Therefore, the option (c) is also incorrect option. Hence, the correct answer is option (d) aseptic.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 12SA
Alcohols are very effective in 70% solution than 100%:
Explanation
Alcohols in cell membrane facilitate diffusion and are effective. 70% alcohol is used as antiseptic when compared to 100% alcohol; since, 70% alcohol facilitates coagulation of protein. Besides, 100% solution causes protein to harden on exterior side of organism. It causes the microorganism to be dormant, but does not lead to death. Thus, 100% alcohol will dry the bacteria, but it will not kill so, in general 70% alcohol is used.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 13MC

  • The Center for Disease Control and Prevention has established biosafety guidelines in microbiological laboratories. BSL-3 is a third level of biosafety, in which there is entry through double sets of doors and ventilation, so air moves into the room through an open door. Air leaving will be HEPA filtered (High-efficiency particulate air) before being discharged outside the room. Therefore, the option (a) is the correct answer.
  • Pressurized suits and showers in entryways are facilities provided under biosafety level 4. They are not considered under BSL-3. Therefore, the option (b) and (c) are incorrect. Option (d) is incorrect, as only one of the given options that is (a) is correct.
    Hence, the correct answer is option (a) double sets of entry doors.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 13SA
Action of quats and soaps:
Explanation
Soaps and quats are surfactants, soaps do not kill microorganism, they will wash off the surfaces, but quats disrupt cellular membrane where the affected cell lose internal ions. In contrast, soaps have hydrophobic end, which have fatty acids and hydrophilic end which is negatively charged. Thus, quats are composed of an ammonium cation in which the hydrogen atoms are replaced by other functional groups.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 14MC

  • Decimal reduction time (D) is the time required to destroy 90% of the microbes in a sample. So, in a sample of E. coli, which has been subjected to heat (lowest temperature) for a specified time, 90% of the cells has been destroyed. So, decimal reduction time will best describe this event. Therefore, the option (c) is correct.
  • Thermal death point is the minimum temperature, which can kill all the microbes in 10 min. Therefore, option (a) is incorrect. Thermal death time is the time required to completely destroy the microbes in a particular volume of liquid at a particular temperature. Therefore, the option (b) is also incorrect. Option (d) is incorrect as one of the given options is correct.
    Hence, the correct option is (c) decimal reduction time.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 14SA
Advantages and disadvantages of using ionizing radiation in food sterilizing:
Explanation
Radiations from electron beams, gamma rays, and X -rays have shorter than 1nm ionizing radiations.
The advantages of using ionization radiations are killing microbes, larvae, and eggs. In addition, it also kills cells that spoil or over ripen fruits and vegetables.
The disadvantages of using ionization radiation are causing of cancer, change taste, and nutritional value of fruits and vegetables.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 15MC

  • Carbolic acid, which is otherwise named phenol, has corrosive properties. Its vapors are corrosive to skin, eyes, and respiratory tract. Repeated exposure to such vapors can lead to dermatitis and even third degree burns. Therefore, option (a) is incorrect.
  • Glutaraldehyde, though it is not carcinogenic, it is highly toxic and acts as strong irritant. Therefore, the option (b) is incorrect.
  • Formalin is a human carcinogen. Exposure to formalin will badly affect the health of a person exposed. Ingestion of formaldehyde will cause death of the person. Thus it is highly toxic to humans. Therefore, the option (d) is incorrect.
  • Hydrogen peroxide is least toxic to humans and is less irritant. It can cause poisoning only when a large amount of liquid comes in contact with eyes and lungs. If poisoned the symptoms like abdominal pain, body aches, temporary change of the skin color etc are observed. These symptoms are not lethal or toxic. Hence, the correct option is (c) hydrogen peroxide.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 15SA
Camper’s remove pathogenic protozoa, bacteria, and viruses in stream water:
Explanation
Water in streams look clean, but have harmful pathogens in water. The pathogens include bacteria, protozoa, and virus. However, the microorganisms in water cause fever and nausea. The infections can be inhibited by short term treatment; for instance, campers. In addition, iodine tablets and drops of chlorine to 2 liters of water can treat stream water to remove pathogenic protozoa, bacteria, and viruses.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 16MC

  • Ethylene oxide, being an alkylating agent, it is a highly reactive sporicidal gas. It can rapidly penetrate and kill the endospores of microorganisms. Ethylene oxide is otherwise named oxirane. It is widely used in hospitals for sterilizing medical equipment, and heat sensitive tools. Therefore, the option (b) is correct.
  • Copper ions cannot penetrate any cell unless there are ion channels for their entry. Therefore, they can show no negative effect on endospores. Thus, option (a) is incorrect.
  • Ethylene can dissolve lipids, but not spore walls of the endospore. It cannot penetrate into the spore wall of endospore. Therefore, option (c) is incorrect.
  • Triclosan is a biocide, with number of membrane and cytoplasmic targets. It can act effectively on vegetative cells, but cannot act on spores. Therefore, the option (d) is also incorrect option.
    Hence, the correct option is (b) ethylene oxide.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 17MC

  • Phenol is the disinfectant, which interferes with the cell membrane of microorganisms. They are active even in the presence of contaminating agents like pus and vomit. Therefore, the option (a) is correct.
  • Peracetic acid interferes with the metabolism of microorganisms, while silver nitrate and gluteraldehyde interferes with protein denaturation. Therefore, the options (b), (c), and (d) are incorrect options. Hence, the correct option is (a) phenol.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 18MC

  • Iodophor is iodine containing organic compound, which slowly releases iodine, a quat is a quaternary ammonium compound used for antimicrobial action and formalin is formaldehyde dissolved in water to make 37% solution. All these compounds do not contain alcohol in them. Therefore, the options (a), (b), and (c) are incorrect.
  • Tinctures are generally solutions of antimicrobial chemicals in alcohol. So, a tincture of bromine contains alcohol. This disinfectant is used in wide areas including space crafts for sterilizing different objects. Hence, the correct option is (d) a tincture of bromine.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 19MC

  • Ethylene oxide is used as an antimicrobial chemical to sterilize spacecraft. NASA (National Aeronautics and Space Administration) uses this gas to sterilize the spacecraft before landing on any new land. Therefore, the option (d) is correct.
  • Phenols are intermediate to low level disinfectants. They can disrupt cell membrane and denature proteins. They are more effective against aerobic microorganisms rather than anaerobic microorganisms. But they are not used in space crafts. Therefore, the option (a) is incorrect.
  • Alcohol has bactericidal, fungicidal, and virucidal properties. They are regarded as intermediate level disinfectants. They are very much effective against aerobic microorganisms, but not used in space crafts. Therefore, the option (b) is incorrect.
  • Heavy metals ions like zinc, silver, mercury, arsenic, and copper can as antimicrobial agents. They have the ability to combine with sulfur atoms present in cysteine molecule and thereby can disrupt the proteins. But, they are not used in space crafts. Thus, the option (c) is incorrect.
    Hence, the correct option is (d) ethylene oxide.

Microbiology with Diseases by Taxonomy Chapter 9 Answers 20MC

  • Surfactants like quaternary ammonium compounds are mostly soluble in water. These are the synthetic detergents, which are more soluble in water than soaps. They are composed of ammonium cation (NH4+) in which the atoms of hydrogen are replaced by some other functional groups. For example, benzalkonium chloride, cetylpyridinium chloride etc. Since they are readily soluble in water, they are used in mouth washes. Thus, the option (a) is correct.
  • Though alcohols are soluble in water they are not readily soluble. Only simple and low carbon alcohols are soluble in water, but not the compounds that contain more number of carbon atoms. Therefore, the option (b) is incorrect.
  • Soaps have fatty acid ends and are less soluble in water compared to quaternary ammonium compounds. Therefore, the option (c) is incorrect.
  • Peracetic acid is more soluble in fats, rather than in water. It is a colorless, pungent, sour smelling liquid. It is included under the group hydroperoxides. Since, it is not water soluble the option (d) is incorrect. Hence, the correct option is (a) quaternary ammonium compounds.

Microbiology with Diseases by Taxonomy Chapter 8 Answers

Microbiology with Diseases by Taxonomy Chapter 8 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 8 Answers 1CM
The polymerase chain reaction (PCR) can be easily described by the following concept map.
microbiology-with-diseases-by-taxonomy-chapter-8-answers-1cm
microbiology-with-diseases-by-taxonomy-chapter-8-answers-1cm1
microbiology-with-diseases-by-taxonomy-chapter-8-answers-1cm2

Microbiology with Diseases by Taxonomy Chapter 8 Answers 1CT
Restriction enzymes cut the DNA (deoxyribonucleic acid) molecules at specific restriction sites on both the strands and produce sticky ends or blunt ends.
If the restriction enzymes make staggered cuts of the two strands of DNA, then fragments having sticky ends will be formed. In table 8.1, BamHI, EcoRI, HindII,I and HinfI will produce restriction fragments with sticky ends.
When the restriction enzyme cut both the strands of DNA at the same point, then fragments having blunt ends will be produced. In table 8.1, EcoRI, HindII, HpaI, MspI, and SmaI will produce blunt ended fragments.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 1L
The following figure shows the various steps of polymerase chain reaction (PCR). The reagents and temperature required at every step have been labeled.
microbiology-with-diseases-by-taxonomy-chapter-8-answers-1l
microbiology-with-diseases-by-taxonomy-chapter-8-answers-1l1
microbiology-with-diseases-by-taxonomy-chapter-8-answers-1l2
Every cycle of PCR consists of three steps. They are:

  1. DENATURATION:
    The hydrogen bonds present between the two strands of DNA are broken in this step. The DNA is heated at 94oC to do so. Due to this the two strands get separated.
  2. PRIMING:
    To the separated DNA strands DNA primers, deoxyribonucleotide triphosphates and DNA polymerase are added. Then the mixture is cooled to 65oC. This allows the binding of primers to the single strands of DNA at their complementary sites. Primers provide a free 3’ end for the enzyme to carry on polymerization.
  3. EXTENSION:
    In this step, the double stranded DNA molecules will be synthesized by the DNA polymerase. Warming speeds the polymerization action of the enzyme. So this step is carried on at 72oC.
  4. REPEAT:
    After the completion of on PCR cycle, two DNA molecules will be synthesized from one DNA molecule. These will act as the target DNA for the next cycle of PCR.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 1MC

  • Biotechnology is the use of microorganisms to develop new useful products for the improvement of quality in human life. This can be achieved by techniques like inducing mutations, tissue culture, recombinant, and DNA technology. Recombinant DNA (deoxyribonucleic acid) technology is a branch of biotechnology. Hence, the option (a) is incorrect.
  • Combinatorial biology is the genetic manipulation of enzymes with the intent of changing the industrial product. The idea is that large number of compounds will be generated. Genetic manipulation can be attained by inducing mutations, recombination, and recombinant DNA technology. Hence, the option (b) is incorrect.
  • By using recombinant DNA technology plants resistant to various conditions, high yielding varieties of both plants and animals, and microbes resistant to various antibiotics that can be developed. Hence, the option (c) is incorrect.
  • Undesirable phenotypic traits can be eliminated in living organisms by the use of recombinant DNA technology. Likewise, beneficial traits of two or more organisms can be combined to develop new organisms. Recombinant DNA technology involves modification of an organism’s genome. They can be achieved by genetic modification.
    Hence, the correct option is (d) it involves modification of organism’s genome.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 1MTF
Movement of DNA is inhibited by restriction enzymes:
Explanation
Restriction enzymes cut DNA (deoxyribonucleic acid) molecules at restriction sites, which have specific nucleotide sequences. They cut both the strands of DNA and produce either sticky or blunt ends. Restriction enzymes are useful in the movement of DNA. The sticky or blunt ends are helpful in recombining DNA molecules. Thus, restriction enzymes are involved in the movement of DNA.
Hence, the given statement, restriction enzymes inhibit the movement of DNA is False.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 1SA
The three artificial methods to introduce DNA (deoxyribonucleic acid) into cells are as follows:

  1. Electroporation
  2. Protoplast fusion
  3. Injection

Electroporation:
By using electric current, microscopic holes are punctured on the cell’s membrane. Through these holes, the DNA from the environment enters into the cell. This method can be used on all types of cells. Afterwards, the cells will repair their membranes and cell walls.
Protoplast fusion:
Protoplasts are cells without cell wall. When protoplasts are made to encounter one another, their cytoplasmic membranes may fuse and form into a single cell. This cell will contain the genomes of both the parent cells. Polyethylene glycol increases the rate of protoplast fusion.
Injection:
This is again of two types. They are gene gun and microinjection. Gold beads coated with DNA are fired into the target cell by using a gene gun. The metal beads are eliminated by the cell. In microinjection, DNA is inserted into the target cell by using a micropipette having a very small diameter.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 2CT
Genetic screening can identify the infection of viruses even before the patient shows any sign of infection.
The cancer inducing virus, Human T-lymphotropic virus 1 or HTLV-1 inserts itself into the human chromosome. There it remains. Thus that particular gene in the human chromosome gets mutated. The mutated gene can be identified by using genetic screening. The scientists use DNA or Deoxyribonucleic acid microarrays to screen patients for such mutated genes.
DNA microarray consists of single-stranded DNA immobilized on a substrate. The DNA from infected cells is immobilized on the substrate. Then a sample DNA which is complementary to the viral DNA is washed over the microarray. This sample DNA is fluorescently labeled. By this, the sample DNA will bind to its complementary DNA if present on the microarray.
The fluorescence will indicate the presence of the viral DNA in the patient’s DNA sample.
In this way, a laboratory technician can prove that the patient is infected with HTLV-1 even when there is no sign of cancer by using genetic screening.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 2MC
Reverse transcriptase:
Reverse transcription is the conversion of HIV’s single stranded RNA into double stranded viral DNA. Usually in cells, DNA is transcribed into RNA. Reverse transcription is catalyzed by reverse transcriptase enzyme. Thus, the enzyme that transcribes an RNA template into a molecule of DNA is reverse transcriptase. Hence, the option (a) is incorrect.
Recombinant DNA:
It is the genetically engineered DNA (deoxyribonucleic acid) created by combining two different DNA molecules isolated from different species. One of the parent cells will act as host for the other. Hence, the option (b) is incorrect.
Probe DNA:
It is a small single-stranded DNA molecule, which is used to identify specific sequences by allowing it to bind to complementarily sequences. Hence, the option (d) is incorrect.
Complementary DNA:
A molecule of DNA that is transcribed by using RNA template is called complementary DNA, as it is complementary to RNA template. Complementary DNA is a DNA gene, which is produced from RNA template.
Hence, the correct option is (b) complementary DNA.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 2MTF
Restriction enzymes act at specific sequence of nucleotides in double stranded molecule:
Explanation
Restriction enzymes cut DNA (deoxyribonucleic acid) molecules only at restriction sites. These sites have specific nucleotide sequences. Such sequences are usually palindromes. Moreover, the restriction enzymes cut both the strands of DNA and produce either sticky or blunt ends.
Hence, the given statement, restriction enzymes act at specific nucleotide sequences within a double-stranded DNA molecule, is True.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 2SA
Cloning is the process of producing similar populations of genetically identical individuals. Each population is called a clone.

  • Cloning involves the selection of cells with required characteristics. Each cell is grown in vitro to develop into a population. The genome of the cells can be manipulated before they are grown.
  • This will result in populations with modified cells. The cells in the population may be modified or may not be modified. The clone may even be contaminated with other cells.
  • In such conditions, the whole procedure should be repeated.
  • The work of medical researchers is usually linked with modifying the characteristics of cells. This is attained by cloning. So the medical researchers usually carry on cloning.
  • For working with cells, the scientists require the cells in more number. Thus, the scientists carry on cloning.
  • By following cloning procedure, animals, plants, and humans can be modified in their characteristics. Such organisms are said to be cloned.
  • The cloned organisms will have an increment in their characteristics.
  • Cloning procedure is completely carried in vitro. Due to these reasons, cloning is a practical technique to medical researchers.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 3CT
A thermocycler is a device that automatically performs Polymerase Chain Reaction (PCR) by continuously cycling through the three temperature regimes (94oC, 65oC, and 72oC).
The Deoxyribonucleic Acid (DNA) polymerase derived from hyperthermophilic bacteria, such as, Taq DNA polymerase remains stable at all the three temperatures used in PCR. It is resistant to temperature fluctuations as well as to the high temperature.
Whereas, the DNA polymerase derived from E.coli denatures when the temperature is increased to 94oC. Thus, if it is used in PCR, the enzyme has to be recovered after every cycle and added when there is a need.
As a thermocycler runs continuously, it does allow adding or recovering of the enzyme in the middle of the program. So, a thermocycler uses only Taq DNA polymerase and cannot use the DNA polymerase that is derived from E.coli.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 3MC
Recombinant cells:
The cells in which recombination has taken place are called as recombinant cells. Hence, the option (a) is incorrect.
Competent:
It is the ability of the cells to take up the external DNA into it. For instance, bacterial cells are treated in chemicals to make them capable of loosening their cell covering, in order to take up the plasmids (vectors). Such a bacterial cell is called competent cell. Hence, the option (b) is incorrect.
Phages:
Viruses that infect bacteria are known as bacteriophages or phages. They can multiply by lytic cycle or lysogenic cycle. Bacteriophage is a virus that infects bacteria. It replicates within the bacteria. Hence, the option (d) is incorrect.
Mutagens:
Mutagens are the physical and chemical agents that induce mutations. They create sudden changes in the genome of the microorganism so that its phenotype is changed. Agents X, Y, and Z altered the fungi Penicillium, so that the type and amount of penicillin produced from it became more effective. These agents are probably mutagens.
Hence, the correct option is (c) mutagens, which induce mutation resulting in the increment of the penicillin production.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 3MTF
Based on the size, shape, and electric charge:
Explanation
A thermocycler is a device that is used to perform PCR (polymerase chain reaction) automatically by continuously cycling the necessary reagents through three temperature regimes. Thus, the thermocycler is used to perform PCR automatically. Moreover, the technique is used to separate the molecules basing on the electrical charge, size, and shape is known as electrophoresis.
Hence, the given statement, a thermocycler separates molecules based on their size, shape, and electrical charge, is False.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 3SA
The nucleic acids (DNA and RNA) synthesized in vitro are called synthetic nucleic acids. Scientists use these nucleic acids mainly in three ways. They are:

  1. Elucidating the genetic code:
    Scientists used synthetic nucleic acids with varying nucleotide sequences. By using them, they synthesized polypeptide chains. They observed the amino acids in the synthesized polypeptides and the codons for every amino acid have been described. In this way, scientists elucidated genetic code by using synthetic nucleic acids.
  2. Creating genes for specific proteins:
    After knowing the genetic code and the amino acid sequence of a protein, the scientists are able to synthesize a gene for that particular protein in vitro.
  3. Synthesizing DNA and RNA probes:
    Probes are small single-stranded nucleic acid molecules, which are mostly used to locate specific nucleotide sequences. These are fluorescently or radioactively labeled, if necessary. Scientists synthesized probes in vitro, such that they are complementary to the sequence of desired DNA (deoxyribonucleic acid).

Microbiology with Diseases by Taxonomy Chapter 8 Answers 4CT
Southern blotting involves the transfer of DNA or Deoxyribonucleic acid fragments from Agarose gel unto nitrocellulose membrane. A sample containing probes, which are complementary to the desired DNA is prepared. The probes are radiolabeled. It is allowed to wash over the membrane. The probes will bind to their complementary sequences on the membrane. The probes bound on the membrane will show radioactivity on the photographic film.
DNA microarray consists of single-stranded DNA immobilized on a substrate. A sample containing fluorescently labeled DNA, which is complementary to the desired DNA, is prepared. It is allowed to wash over the DNA microarray. The sample DNA will bind to the desired DNA sequences. Fluorescence will be shown representing the presence of the desired DNA sequences.
The similarity in these results is identifying the sequence by using complementary sequence. Fluorescence or radioactivity will be shown only at the places, where complementary DNA sequences are present. Both of these techniques can be used to diagnose infections.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 4MC
Vectors are small enough to manipulate outside a cell:
The DNA molecules that are used as vectors are small. If they are large it will be difficult to manipulate them in the laboratory. Thus, the vectors are small to facilitate their manipulation in-vitro. Hence, the option (a) is correct.
Vectors contain a recognizable genetic marker:
The vectors carry vehicles of the desired DNA fragment. To identify the cells that contain the desired DNA fragment, it is necessary to identify the presence of vector in the cell. So, the vectors contain genetic markers like antibiotic resistance, coding for unique enzymes, radioactive labels, and fluorescent labels. Hence, the option (b) is correct.
Vectors survive inside cells:
Vectors are vehicles of the desired DNA fragment. They should be stable until the purpose of the desired DNA fragment is fulfilled. So, the vectors are stable and survive inside the host cell. Plasmids make good vectors. Hence, the option (c) is correct.
Vectors must contain genes for self-replication:
Vectors are usually meant for gene expression. Thus, the vectors must contain promoter. They can replicate along with the host genome. So, it is not necessary that the vectors must compulsorily contain genes for self-replication. Vectors are the vehicles used to deliver a foreign gene into a cell.
Hence, the correct option is (d) Vectors may not contain genes for self-replication.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 4MTF
In genetic modification protoplast fusion is used:
Explanation
Protoplast is a cell without cell wall. When two such cells encounter each other, their cytoplasmic membranes may fuse resulting in a single cell. The resultant cell will contain the genomes of both the cells. Moreover, this causes a chance in recombining of two DNA (deoxyribonucleic acid) molecules from the fused cells. Thus, a recombinant DNA molecule is formed and the resultant recombinant DNA molecule leads to genetic modification of particular cell.
Hence, the given statement, protoplast fusion is often used in the genetic modification of plants, is True.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 4SA
Gene library:
It is a collection of bacterial or phage clones containing either all the genes of the entire genome of an organism or cDNA (complementary deoxyribonucleic acid) that is complementary to the organism’s mRNA (mitochondrial ribonucleic acid).

  • A clone contains a single gene of the entire organism’s genome and it is like a book in the library.
  • A clone in a gene library can be created by making the DNA into fragments by using restriction enzymes. The desired fragments are selected and inserted into the vectors. Such vectors are introduced into the host cells.
  • The recombinant cells are identified after growing on culture media. Each type of recombinant cells will represent a clone. This clone will contain the desired DNA fragments.
  • Once a recombinant clone has been placed in the gene library, it will be made available to all the investigators. This saves their time and effort required to isolate that gene. Thus, it is very useful.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 5CT
HhaI restriction enzyme is derived from Haemophilus haemolyticus. It cuts the Deoxyribonucleic Acid or DNA sequence at the sites as indicated below:
G-C-G-C
C-G-C-G
By cutting at these sites, fragments having sticky ends will be produced, as this is a staggered cut. The fragments produced will be as follows:
G- -C-G-C
C-G-C- -G
The sticky ends produced by this enzyme are having only two nucleotides. These ends have the capability of rejoining or bind to other complementary nucleotide sequence. This enzyme can be used to construct recombinant DNA molecules.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 5MC
Gel electrophoresis:
The method of separation and analyzation of the macromolecules like DNA, RNA, and proteins based on their size and charges is called as gel electrophoresis. A mixture of DNA fragments is placed at one end of the porous agarose gel and an electric voltage is applied to the gel. It is the technique used to separate DNA fragments basing on their electrical charge, size and shape. Hence, the option (b) is incorrect.
Electroporation:
It is the technique used to introduce DNA from the environment into the cells by using an electrical current. The plant cells are exposed to electric field in order to generate holes in the cell membrane. The new DNA is then transferred via the holes. Hence, the option (c) is incorrect.
Reverse transcription:
The process of synthesizing a DNA gene from an RNA template is called reverse transcription. In this process, reverse transcriptase is used. Hence, the option (d) is incorrect.
The recombinant DNA technique that is used to replicate copies of a DNA molecule is PCR. Polymerase chain reaction is the technique used to produce a large number of identical copies of DNA in a laboratory. This can be automated by using a thermocycler.
Hence, the correct option is (a) PCR, which is the recombinant DNA procedure for replicating copies of DNA molecule.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 5MTF
Gel electrophoresis is not used in DNA microarrays:
Explanation
In gel electrophoresis, agarose gel acts as a molecular sieve and separates the DNA (deoxyribonucleic acid) fragments basing on their electrical charge, size, and shape. DNA microarray consists of single-stranded DNA immobilized on a substrate. This is usually used to identify specific DNA sequences. Fluorescently labeled single-stranded DNA is allowed to bind to their complementary sequences, which are the desired DNA sequences.
Hence, the given statement, gel electrophoresis is used in DNA microarrays, is False.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 5SA
Recombinant DNA (deoxyribonucleic acid) technology is a collection of tools or techniques used to manipulate organism’s genome. It has vast applications like gene mapping, medical, and agricultural applications.
Besides applications, it is facing many problems. The three potential problems of recombinant DNA technology are as follows:

  1. Concern over the accidental release of altered organisms into the environment:
    As recombinant DNA technology is developing, the focus on it is increasing. The government is imposing pressure on the laboratories for its development. Due to this, the accidental release of altered organisms into the environment is lacking interest.
  2. Ethics of altering animals for human use:
    Recombinant DNA technology is solely used for developing products useful to the mankind. This involves altering the animals for human use. The animals’ value is being decreased. Only human is given importance.
  3. Potential for creating genetically modified biological weapons:
    Recombinant DNA technology is intended to produce beneficial crops and animals. Sometimes, this may get reversed. This results in the creation of biological weapons, which are more infective and more resistant to treatment. An example of this is Bacillus anthracis spores, which are used in bioterrorist attack.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 6CT
Polymerase Chain Reaction (PCR) of DNA is similar to bacterial population growth.
Every cycle of PCR doubles the number of DNA.
The number of DNA molecules present at the end of all the PCR cycles can be calculated by using the formula:
N = X × 2 n
Where, N = Total number of double stranded Deoxyribonucleic acid (dsDNA) molecules formed after the completion of the respective cycles of PCR,
X = Starting number of dsDNA molecules and
n = Number of PCR cycles.
The number of DNA molecules present after 15 cycles of PCR starting with 15 dsDNA molecules will be:
N = X × 2n
N = 15 × 215
= 15 × 32768
= 491520
In total, 491520 dsDNA molecules will be present after the completion of 15 cycles of PCR started with 15 DNA helices.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 6MC
Southern blotting:
In this method, the DNA fragments from agarose gel are transferred to nitrocellulose membrane. Later, specific sequences are identified by using probes. Hence, the option (a) is incorrect.
Reverse transcription:
The process of synthesizing a DNA gene from an RNA template is called reverse transcription. In this process, reverse transcriptase is used. Hence, the option (b) is incorrect.
Restriction enzymes:
Restriction enzymes cut the double stranded DNA at the recognition sites. The enzymes cut DNA molecules at specific restriction sites and produce sticky or blunt ends. Hence, the option (d) is incorrect.
DNA microarray:
DNA microarray consists of single-stranded DNA molecules immobilized on a substrate. This is used to monitor, which genes are transcribing at a particular time in a cell. For this, fluorescently labeled cDNA strands are allowed to bind to complementary sequences on the DNA microarray. The sites of fluorescence reveal the genes that are transcribing at that particular time. Thus, in monitoring gene expression in a yeast cell, DNA microarray is most useful.
Hence, the correct option is (c) DNA microarray.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 7CT
In the gene TACAATCGCATTGAA, the codons are TAC, AAT, CGC, ATT and GAA. In these codons, the fourth codon (ATT) is complementary to the translation termination codon UAA (ochre).
Thus, the Ribonucleic acid (RNA) containing the anticodon UAA could be used to stop translation directly of that particular gene.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 7MC
In the study of genomics, sequencing of fluorescent nucleotide bases is used regularly.
Fluorescent nucleotide bases are sequenced:
In a cDNA, the nucleotides are labeled with fluorescent dyes. The four nucleotides are labeled with different color. Automated DNA sequencer determines the sequence basing on the colors emitted by the nucleotides. This sequencing and analysis of nucleotides is involved in genomics.
Hence, the option (c) is correct.
Clones are selected using a vector with two genetic markers:
Recombinant clones can be identified easily when vectors with two genetic markers are used. For example, the genetic markers are antibiotic resistance. Then, the cells will be grown on the media containing both the antibiotics. The cells which grow on such media will be the recombinant cells. This selection is based on phenotypic character.
Hence, the option (a) is incorrect.
Genes are inserted to produce an antigenic protein from a pathogen:
A pathogenic cell can be made capable to produce an antigenic protein by using recombinant DNA (deoxyribonucleic acid) technology. The gene that is coding for the antigenic protein is inserted into the cell. This will be a development for phenotypic character.
Hence, the option (b) is incorrect.
Defective organs are replaced with those made in animal hosts:
By using tissue culture technique, animal organs can be propagated. These propagated in animal hosts. These organs can be used as a replacement for the defective organs in the animals.
Hence, the option (d) is incorrect.
Since, the study of genomics involves the sequencing and analysis of fluorescent nucleotide bases, the correct option is (c) Fluorescent nucleotide bases are sequenced.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 8CT
A particular congenital disease is caused by synthesis of a protein, which is produced by a mutated gene. In such cases, researchers use gene therapy to prevent translation of that particular protein.
Some of the genetically defective cells are removed from the patient. These defective cells are those that produce defective protein.
The genes responsible for production of defective protein will be removed. These genes are replaced by normal genes. The cells containing the normal genes will be replaced in the patient.
The vectors can be used to deliver genes directly into the target cells within the patients.
This will result in the removal of the defective genes, thereby, preventing the translation of the defective protein.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 8MC

  • Restriction enzyme HhaI cuts the DNA at a specific nucleotide sequence.
    Restriction enzymes cut the DNA (deoxyribonucleic acid) molecule at specific restriction sites. After cutting, the DNA ligase will ligate the fragments. Meanwhile, the fragments may be exchanged.
  • Thus, the restriction enzymes are participating in recombining DNA molecules. But, they alone cannot recombine DNA. Hence, the option (a) is incorrect.
  • Every restriction enzyme cuts the DNA molecule at specific nucleotide sequences. Such sites are called restriction sites. The sequences at these restriction sites are usually palindromes.
  • The ends produced after cutting will be either sticky or blunt. This is based on the type of cut. Hence, the option (b) is incorrect.
  • Restriction enzyme HhaI is likely derived from Haemophilus influenzea is incorrect statement. Restriction enzyme HhaI is derived from Haemophilus haemolyticus. Hence, the option (c) is incorrect.
  • As only one option is correct, the option (d) all of the above is incorrect.
  • Since, the restriction enzyme HhaI cut DNA at a specific nucleotide sequence, the correct option is (b) cuts DNA at a specific nucleotide sequence.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 9MC
The recombinant DNA technology that involves the production of a distinct pattern of DNA fragments on a gel is genetic fingerprinting.
Genetic fingerprinting:
DNA fingerprinting involves producing multiple copies of the sample DNA by using PCR. These copies of DNA are made into fragments by adding restriction enzymes. The resultant fragments are separated by gel electrophoresis to produce a unique pattern. These patterns are compared with that of known fingerprints.
Hence, the option (a) is correct.
Gene therapy:
Diseases can be cured by using gene therapy. For this, the defective cells from the patients are isolated. Then the defective genes in the cell are replaced by normal genes. Now these cells are replaced into the patient.
Hence, the option (b) is incorrect.
Genetic screening:
Viral DNA sequences in a patient’s blood or other tissues can be identified by genetic screening. Moreover, it can identify the disease even before the patient show any symptom.
Hence, the option (c) is incorrect.
Protein synthesis:
The process of synthesizing a polypeptide chain from an RNA template is called as translation. After this, post-translational modifications take place to make the polypeptide chains into active proteins.
Hence, the option (d) is incorrect.
Hence, the correct option is (a) genetic fingerprinting, which is the technique that involves the production of a distinct pattern of DNA fragments on a gel.

Microbiology with Diseases by Taxonomy Chapter 8 Answers 10MC
A DNA microarray consists of single-stranded DNA localized on a substrate.
Single-stranded DNA localized on a substrate:
A DNA (deoxyribonucleic acid) microarray consists of single-stranded DNA molecules immobilized on glass slides, silicon chips, or nylon membranes. Fluorescently labeled single-stranded DNA will adhere to the complement strand. Hence, the option (d) is correct.
A series of clones containing the entire genome of a microbe:
The collection of clones containing the entire genome of an organism is called a gene library. It may also contain the set of cDNA (complementary DNA) that is complementary to the organism’s mRNA. Each clone of this will represent a gene. Hence, the option (a) is incorrect.
Recombinant microbial cells:
Recombinant microbial cells are those that carry recombinant DNA usually in a vector. These are meant for fulfilling the purpose of recombinant DNA technology. Hence, this option (b) is incorrect.
Restriction enzymes fragments of DNA molecules:
Restriction enzymes cut the DNA molecules and produce double-stranded DNA fragments with sticky or blunt ends. Such DNA molecules are useful in forming recombinant DNA molecules. As the fragments double-stranded, they are not directly useful in identifying specific sequences. Hence, the option (c) is incorrect.
Hence, the correct option is (d) single-stranded DNA localized on a substrate. A DNA microarray consists of single-stranded DNA localized on a substrate.

Microbiology with Diseases by Taxonomy Chapter 7 Answers

Microbiology with Diseases by Taxonomy Chapter 7 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 7 Answers 1CM
microbiology-with-diseases-by-taxonomy-chapter-7-answers-1cm
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Microbiology with Diseases by Taxonomy Chapter 7 Answers 1CT
DNA of nucleotides used as template for replication and transcription, with radioactive deoxyribose as template:
Explanation
Deoxyribonucleic acid (DNA) encodes genetic instructions in all living organisms. It is a nucleic acid, composed of major macro molecules, containing double-stranded helices. It organized into long structures known as chromosomes. Moreover, it is used in genetic engineering, forensics, bioinformatics, and DNA nanotechnology.
Similarly, ribonucleic acid (RNA) is a biological molecule, which plays an important role in coding, decoding regulation, and expression of genes. However, it is usually single-stranded and plays an important role in the cells by catalyzing reactions.
The percentage of DNA and RNA strands that are radioactive after DNA replication are:
Explanation
After completion of DNA replication cycles, DNA strand contain 12.5 % of radioactive sugars. Therefore, in RNA molecules do not contain radioactive sugars, because it uses only ribose sugar, whereas in experiment only deoxyribose is radioactive.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 1FB
The three steps in RNA transcription are initiation, elongation, and termination.
Cells first make an RNA (ribonucleic acid) copy of the gene; this process is known as transcription. In RNA transcription three steps are involved, they are initiation of transcription, elongation, and termination.
RNA polymerase is an enzyme, which produces RNA. It attaches to the promoters (specific nucleotide sequences) that is located in the beginning of the gene and initiates the transcription. It transcribes the DNA template in to RNA. RNA is produced in 5’-3’ direction.
In elongation, RNA polymerase moves down the DNA template to synthesize RNA.
Finally RNA polymerase falls off on the 5’ end of the DNA template. It leads to the termination of the transcription.
Hence, the correct answers are initiation, elongation, and termination.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 1L
The given diagram is showing the discontinuous synthesis of a lagging strand during DNA replication.
The parts a, b, c, d, e, f, g, h, i, j, k and l can be identified as listed below:
a. Replication fork:
It is the spot at which both strands of DNA get separated to allow replication of individual strands.
b. Stabilising proteins:
They help in unwinding and parting of the two strands of the DNA molecule.
c. Nucleotide trisphosphate:
These are the main components of nucleic acids. They not only provide energy but also give phosphate groups during phosphorylation reactions.
d. Leading strand:
This is strand produced in continuation in 5’ to 3’ direction due to polymerization.
e. Helicase (enzyme):
It is an enzyme which is responsible for separation of double helical strands of DNA.
f. Primase (enzyme):
It is the enzyme that builds short RNA molecules complementary to the DNA template.
g. DNA polymerase III (enzyme):
This is the enzyme involved in the proof reading function when nucleotides are being added to the new strand.
h. RNA primer:
It is a small strand composed of nucleic acids and is the starting point to begin DNA synthesis.
i. Okazaki fragments:
The short segments of DNA on the lagging strand during replication. These are joined as one by an enzyme ligase.
j. DNA polymerase I (enzyme):
It is the enzyme which removes the RNA primer. RNA primer is replaced by the DNA. It also plugs in the required nucleotides amid the Okazaki fragments.
k. Lagging strand:
The newly formed discontinuous strand opposite to replication fork in leading strand in 3’ – 5’ direction.
l. Ligase (enzyme):
This enzyme is responsible for filling the gaps in sugar phosphate back bone of the DNA. It also helps in joining the Okazaki fragments.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 1MC
An organized structure of DNA (deoxyribonucleic acid), protein and RNA (ribonucleic acid) found in cells is known as chromosome. It contains DNA-bound proteins which serve packaging the DNA and controls it functions.
a) 4,000,000 base pairs:
Each cell contains more than one type of chromosome. Chromosomes are existed as either duplicated (two identical copies) or unduplicated (single duplicated strands).
In eukaryotes linear chromosome is present whereas in prokaryotes small circular chromosome is present.
In eukaryotes chromosomes are packed by proteins into a condensed structure is known as chromatin. In bacterial chromosomes the 4,000,000 base pairs are present. Hence, this option is correct.
b) 4000 base pairs:
Each cell contains more than one type of chromosome. Chromosomes are existed as either duplicated (two identical copies) or unduplicated (single duplicated strands).
In eukaryotes linear chromosome is present whereas in prokaryotes small circular chromosome is present.
In eukaryotes chromosomes are packed by proteins into a condensed structure is known as chromatin. In bacterial chromosomes the 4,000,000 base pairs are present. Hence, this option is incorrect.
c) 400 base pairs:
Each cell contains more than one type of chromosome. Chromosomes are existed as either duplicated (two identical copies) or unduplicated (single duplicated strands).
In eukaryotes linear chromosome is present whereas in prokaryotes small circular chromosome is present.
In eukaryotes chromosomes are packed by proteins into a condensed structure is known as chromatin. In bacterial chromosomes the 4,000,000 base pairs are present. Hence, this option is incorrect.
d) 40 base pairs:
Each cell contains more than one type of chromosome. Chromosomes are existed as either duplicated (two identical copies) or unduplicated (single duplicated strands).
In eukaryotes linear chromosome is present whereas in prokaryotes small circular chromosome is present.
In eukaryotes chromosomes are packed by proteins into a condensed structure is known as chromatin. In bacterial chromosomes the 4,000,000 base pairs are present. Hence, this option is incorrect.
Hence, the correct option is (a) 4,000,000 base pairs which is the present in the bacterial chromosome.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 1SA
Genotype of bacterium determines its phenotype:
Explanation
Set of genes in the genome is known as genotype of an organism. Physical features and function traits of an organism is known as phenotype. Examples are antibiotic resistance, morphology, structure, and metabolism. Moreover, it is mainly used in determining the difference in genetic makeup of an individual by observing the DNA sequence of biological assays.
The following methods of genotyping, which includes are:

  1. Restriction fragment length polymorphism identification (RFLPI).
  2. Amplified fragment length polymorphism detection (AFLPD).
  3. Random amplified polymorphic detection (RAPD).
  4. DNA sequencing.
  5. Polymerase chain reaction (PCR).
  6. Allele specific oligonucleotide (ASO).

Similarly, genotype of bacteria is encoded by gene in DNA, which is transcribed into mRNA. The mRNA is translated into protein (polypeptide). In this translation, ribosomes play an important role.
Thus, a bacterium contains different genotypes with different proteins and determines different phenotype.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 2CT
The amino acid sequences in polypeptide are synthesized by eukaryotic ribosomes:
Explanation

  1. Messenger RNA is large family of molecules. They transmit genetic information to DNA and to ribosome.
    Transcription of mRNA is followed by the RNA polymerase, and then it translated to polymers of amino acids and proteins.
  2. In DNA mRNA genetic information is determined in nucleotide sequence.
  3. If mRNA have the nucleotide base sequences, then sequence of amino acids in polypeptides are synthesized by eukaryotic ribosomes.

The sequence of amino acids in polypeptides is synthesized by eukaryotic ribosomes by the following below.

  • AUGGGGAUACGCUACCCC
    Met-Gly-Ile-Arg-Tyr-Pro
  • CCGUACAUGCUAAUCCCU
    Pro-Tyr-Met-Leu-Ile-Pro
  • CCGAUGUAACCUCGAUCC
    Pro-Met (stop)
  • AUGCGGUCAGCCCCGUGA
    Met-Arg-Ser-Ala-Pro (stop

Microbiology with Diseases by Taxonomy Chapter 7 Answers 2FB
A triplet nucleotide sequence that specifies a particular amino acid is known as codon.
The mRNA (messenger RNA) is large family of the RNA and it transmits genetic information from DNA (deoxyribonucleic acid) to the ribosome.
It mainly involves in transcription, transport and translation. Important function of mRNA carries genetic information.
Genetic codon is a set of rules by which the information stored in DNA or RNA is translated into proteins. Generally the codon is a sequence of three nucleotides called triplet. Each triplet specifies one amino acid during protein synthesis.
Hence, the correct answer is codon.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 2MC
Prokaryotic chromosomes are circular and they are present in the cytosol.
a) They typically have two or three origins of replication:
In prokaryotes genome is made by the plasmid and chromosome. They contain only one chromosome.
They contain circular chromosome and introns are absent. In prokaryotes nucleus is absent and chromosome is present in the cytosol.
Their DNA (deoxyribonucleic acid) is naked that means nucleosomes are absent. They are haploid and their chromosome is unpaired. They contains single molecule of circular DNA. Hence, this option is incorrect.
b) They contain single-strand DNA:
In prokaryotes genome is made by the plasmid and chromosome. They contain only one chromosome.
They contain circular chromosome and introns are absent. In prokaryotes nucleus is absent and chromosome is present in the cytosol.
Their DNA is naked that means nucleosomes are absent. They are haploid and their chromosome is unpaired. They contains single molecule of circular DNA. Hence, this option is incorrect.
c) They are located in the cytosol:
In prokaryotes genome is made by the plasmid and chromosome. They contain only one chromosome.
They contain circular chromosome and introns are absent. In prokaryotes nucleus is absent and chromosome is present in the cytosol.
Their DNA is naked that means nucleosomes are absent. They are haploid and their chromosome is unpaired. They contains single molecule of circular DNA. Hence, this option is correct.
d) They are associated in linear pairs:
In prokaryotes genome is made by the plasmid and chromosome. They contain only one chromosome.
They contain circular chromosome and introns are absent. In prokaryotes nucleus is absent and chromosome is present in the cytosol.
Their DNA is naked that means nucleosomes are absent. They are haploid and their chromosome is unpaired. They contains single molecule of circular DNA. Hence, this option is incorrect.
Hence, the correct option is (c) they are located in the cytosol which is the location prokaryotic chromosomes are present.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 2SA
Eukaryotic messenger RNA differs from prokaryotic mRNA:
Explanation
In prokaryotes, the site of transcription and translation of mRNA is cytoplasm. In eukaryotes, transcription occurs in the nucleus and translation of mRNA occurs in the cytoplasm. In addition, prokaryotic mRNA is not modified in transcription, whereas in eukaryotes mRNA is modified in transcription by RNA splicing. Eukaryotic mRNA has only one site for initiation and termination of the protein synthesis, whereas in eukaryotes mRNA is monocistronic.
Furthermore, in eukaryotes mRNA is synthesized from DNA (deoxyribonucleic acid) template. Therefore, in prokaryotes mRNA is being transcribed from the DNA molecule.
Prokaryotic mRNA lifespan is very short, whereas eukaryotic mRNA has longer life span and they are metabolically stable. In eukaryotes transcribed mRNA involves major post transcriptional modifications, whereas prokaryotes undergoes little post transcriptional modifications
Thus, these are the main differences between prokaryotic mRNA and eukaryotic mRNA.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 3CT
Drugs ddC and AZT are used in AIDS treatment:
Explanation
Deoxyribonucleic acid (DNA) encodes genetic instructions in all living organisms. It is a nucleic acid, composed of major macro molecules. Moreover, it contains double-stranded helices and organized into long structures known as chromosomes. Additionally, it is used in genetic engineering, forensics, bioinformatics, and DNA nanotechnology.
Similarly, the drugs ddC (dideoxycytidine) and ATZ (azidothymidine) are mainly used in the treatment of the AIDS (acquired immunodeficiency syndrome). Besides, ATZ is a nucleoside analog, reverse transcriptase inhibitor. It is an antiretroviral drug used for treatment of AIDS.
Therefore, the drugs ddC and ATZ are nucleotide analog bases, in DNA. These drugs are incorporated in the strand of DNA; they bring to an end in the replication of new DNA strand.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 3FB
Three effects of point mutations are silence, missense, and non-sense.
Point mutations replace the single base nucleotide with another nucleotide of the genetic material DNA (deoxyribonucleic acid) or RNA (ribonucleic acid). It occurs at the single point during DNA replication.
They are arising from the spontaneous mutations. The rate of mutations is increased by mutagens like UV rays and X-rays. Three effects of point mutations are silence, missence and nonsense mutations.
Silence mutations code for the same amino acid, and hence it does not show any effect on the protein functioning. A single nucleotide change in this mutation, but the new codon codes for the same amino acid as wild type.
Missense mutations code for entirely different amino acid.
Nonsense mutations code for a stop codon that terminates the protein synthesis. It converts a functional codon into a termination codon.
Hence, the correct answers are silence, missense, and non-sense.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 3MC
a) A molecule of RNA (ribonucleic acid ) found in bacterial cells:
An extra chromosomal genetic material is known as plasmid. They are circular deoxyribonucleic acids which are replicate individually of the bacterial chromosome.
They are commonly found as small circular and double stranded DNA (deoxyribonucleic acid) molecules in bacteria. They also present in eukaryotes and archaea.
They are also considering as replicons because they replicate autonomously with in suitable host. They are mainly used as vectors for molecular cloning. Hence, this option is incorrect.
b) A distinguished from a chromosome by being circular:
An extra chromosomal genetic material is known as plasmid. They are circular deoxyribonucleic acids which are replicate individually of the bacterial chromosome.
They are commonly found as small circular and double stranded DNA molecules in bacteria. They also present in eukaryotes and archaea.
They are also considering as replicons because they replicate autonomously with in suitable host. They are mainly used as vectors for molecular cloning. Hence, this option is incorrect.
c) A structure in bacterial cells formed from plasma membrane:
An extra chromosomal genetic material is known as plasmid. They are circular deoxyribonucleic acids which are replicate individually of the bacterial chromosome.
They are commonly found as small circular and double stranded DNA molecules in bacteria. They also present in eukaryotes and archaea.
They are also considering as replicons because they replicate autonomously with in suitable host. They are mainly used as vectors for molecular cloning. Hence, this option is incorrect.
d) Extra chromosomal DNA:
An extra chromosomal genetic material is known as plasmid. They are circular deoxyribonucleic acids which are replicate individually of the bacterial chromosome.
They are commonly found as small circular and double stranded DNA molecules in bacteria. They also present in eukaryotes and archaea.
They are also considering as replicons because they replicate autonomously with in suitable host. They are mainly used as vectors for molecular cloning. Hence, this option is correct.
Hence, the correct option is (d) extra chromosomal DNA which is known as plasmid.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 3SA
Contrast and comparison of introns and exons:
Explanation
Introns are the nucleotide sequence and exons are the nucleic acid sequence, which are related to genes. Moreover, introns are placed between the exons, whereas exons contain code for the complete protein.
Additionally, introns are non-coding sequence and do not carry genetic information and they don’t involve with the coding of proteins, whereas exons are coding DNA sequence and code for proteins.
Furthermore, introns are spliced out by the RNA (ribonucleic acid) splicing mechanism after transcription, whereas exons join them. Introns do not contain any open reading frame (ORF). They have only stop codons and random sequences.
Thus, exons are named as DNA (deoxyribonucleic acid) bases that are translated into mRNA. Introns are present in the genome of the higher vertebrates.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 4CT
Insertion of three nucleotides is less likely result in deleterious effect than an insertion of single nucleotide:
Explanation
Nucleotides are organic molecules. They are building blocks of the nucleotides (DNA and RNA). They carry energy within the cell and also involve in cell signaling. They are composed of nucleobase, a five carbon sugar, and one or more phosphate groups. They play important role in the metabolism.
Additionally, insertion of three nucleotides gives complete codon to a sequence. It results in incorporation of an amino acid into polypeptide product. Polypeptides have regions, which are flexible for extra amino acid without force.
Furthermore, insertion of a single nucleotide into gene sequence produces a shift of the entire reading frame. It results in the changes in the all codons of the downstream insertion.
Thus, the gene product has an entirely unusual amino acids sequence downstream of the insertion and is non-functional.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 4FB
Insertion and deletions in the genetic code are also called frame shift mutations.
Point mutations replace the single base nucleotide with another nucleotide of the genetic material DNA (deoxyribonucleic acid) or RNA (ribonucleic acid). It occurs at the single point during DNA replication. It includes insertion, deletions and substitutions.
They are arising from the spontaneous mutations. The rate of mutations is increased by mutagens like UV rays and X-rays.
Insertion and deletion of a base pair is called frame shift mutations. In this mutation nucleotide triplets are displaced and creates new sequence of codons, it results in altered polypeptide sequences that mainly affect proteins.
A frameshift mutation is caused by deletion or insertion of a nucleotide in a codon. Due to the triplet nature of a reading frame, any insertion or deletion results in a complete different translation. This affects the protein being synthesized.
Hence, the correct answer is frame shift mutation.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 4MC
a) Chromatin:
it is combination of DNA (deoxyribonucleic acid) and protein which makes the content of the nucleus of the cell. Their main functions are packaging DNA in to a small volume to fit in the cell, to strength the DNA to allow mitosis and DNA damage prevention. It also controls gene expression and DNA replication. Hence, this option is incorrect.
b) Bacteriocin:
a proteinaceous toxin produced from the bacteria is known as bacteriocin. It inhibits the growth of similar bacterial strains. It is narrow spectrum antibiotic. Hence, this option is incorrect.
c) Histone:
Histones are many small, basic proteins most commonly found in association with the DNA in the chromatin of eukaryotes.
They are chief protein component of chromatin. They play very important role in the gene regulation.
They undergo post transcriptional modifications which alter their interaction with DNA and nuclear proteins.
They are basic proteins and their positive charge forms ionic bonds with eukaryotic DNA and stabilizes it. Hence, this option is correct.
d) Nucleosome:
it is a basic unit of DNA packaging in eukaryotic cells. They form fundamental repeating units of eukaryotic chromatin. Hence, this option is incorrect.
Hence, the correct option is (c) histone which is basic protein and their positive charge forms ionic bonds with eukaryotic DNA and stabilizes it.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 4SA
Regulation synthesizes to conserve energy in cells:
Explanation
Polypeptide synthesis is also known as protein synthesis. Biological cells synthesis new proteins, known as polypeptide synthesis. Moreover, it balances by loss of cellular proteins through degradation, assembly of the proteins by ribosomes. It involves in two steps; transcription and translation and differs in prokaryotes and eukaryotes. For example, photosynthesis is best example for polypeptide synthesis. In photosynthesis, the light energy is converted into chemical energy and depends on the light, carbon dioxide, and temperature.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 5CT
The lac operon is an operon, which requires transport and metabolism of the lactose in Escherichia coli and some enteric bacteria. Moreover, it contains lacZ, lacY, and lacA structural genes. These genes are instructed by the enzymes, β-galactosidase, lactose permease, and thiogalactoside transacetylase.
Similarly, E. coli withstands mutation in the gene for lac operon repressor. The mutation in lac operon prevents repressor binding to the promoter, which results in the continuous transcription of the lac operon genes.
Additionally, the continuous production of enzymes is bacterium is catabolized to lactose. However, continuous production of wild type is disadvantage to cells the lac enzymes is. This is because in continuous production of enzyme if no lactose is available, it leads to the waste cellular resources.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 5FB
An operon consists of promoter, operator and series of genes and is associated with a regulatory gene.
Functioning unit of genomic DNA (deoxyribonucleic acid) is known as operon. It consists of promoter, operator and series of genes. It controls the cluster of genes under the promoter.
Promoter is a specific nucleotide sequence on DNA (deoxyribonucleic acid) that initiates and allows gene transcription. It is located on the same DNA strand that will be transcribed and is situated upstream of the sequence towards the 3’ region. The promoter sequence will be recognized by RNA (ribonucleic acid) polymerases and by transcription factors. These sequences are usually 100 to 1000 base pairs in length.
Operator is a segment of the DNA, which is regulator binding. It is defined as a segment between promoter and the series of genes. It is the site where transcription factors bind. The main function of the operator is to regulate the expression of the gene. The function of the operator is explained very clearly in lac operon.
Series of genes are co-regulated by the operon. These genes code for the enzymes that are necessary for metabolic pathway. For instance, the series of genes present in lac operon are lacZ, lacY, and lacA. They code for different proteins and enzymes that are required in lactose metabolism.
Hence, the correct answers are promoter, operator, and series of genes.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 5MC
Nucleotides are organic molecules which forms basic building blocks of the nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
a) Carry energy:
In DNA replication process two identical copies are produced from the original DNA molecule. DNA replication is semi conservative model because each strand of the DNA serves as template for the production of complementary strand.
In this process DNA polymerase produce new DNA strand by adding complimentary nucleotides to the template strand. The nucleotide is carry energy in this process.
Nucleotides are found in four forms, each with a deoxyribose sugar, a phosphate and a base. They are present in the cytosol of the cells as triphosphate nucleotides. Hence, this option is correct.
b) Are found in four forms, each with a deoxyribose sugar, a phosphate and a base:
In DNA replication process two identical copies are produced from the original DNA molecule. DNA replication is semi conservative model because each strand of the DNA serves as template for the production of complementary strand.
In this process DNA polymerase produce new DNA strand by adding complimentary nucleotides to the template strand. The nucleotide is carry energy in this process.
Nucleotides are found in four forms, each with a deoxyribose sugar, a phosphate and a base. They are present in the cytosol of the cells as triphosphate nucleotides. Hence, this option is correct.
c) Are present in the cytosol of the cells as triphosphate nucleotides:
In DNA replication process two identical copies are produced from the original DNA molecule. DNA replication is semi conservative model because each strand of the DNA serves as template for the production of complementary strand.
In this process DNA polymerase produce new DNA strand by adding complimentary nucleotides to the template strand. The nucleotide is carry energy in this process.
Nucleotides are found in four forms, each with a deoxyribose sugar, a phosphate and a base. They are present in the cytosol of the cells as triphosphate nucleotides. Hence, this option is correct.
d) All of the above:
In DNA replication process two identical copies are produced from the original DNA molecule. DNA replication is semi conservative model because each strand of the DNA serves as template for the production of complementary strand.
In this process DNA polymerase produce new DNA strand by adding complimentary nucleotides to the template strand. The nucleotide is carry energy in this process.
Nucleotides are found in four forms, each with a deoxyribose sugar, a phosphate and a base. They are present in the cytosol of the cells as triphosphate nucleotides. Hence, this option is correct.
Hence, the correct option is (d) all of the above which is nucleotides are used in the replication of DNA for caring energy. They are found in four forms, each with a deoxyribose sugar, a phosphate and a base and they are present in the cytosol of the cells as triphosphate nucleotides.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 5SA
Operon model in gene regulation:
Explanation
Operon is functioning unit of the genomic DNA. It is related to regulons, stimulons and modulons. It exists in both prokaryotes and eukaryotes. They are also found in viruses like bacteriophages. Moreover, it was discovered by Jacob and Jacques Monod. Operon has three parts operator, promoter, and repressor.
In addition, during stress circumstances the repressor is bound to the RNA (ribonucleic acid) promoter. Moreover, it increases the RNA polymerase to bind the operator and structural genes of enzymes, which are important for breakdown of the sugars. Thus, in this way operon regulates the gene expression.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 6CT
Nucleotide analogs can be carcinogenic:
Explanation
Nucleotide analogs resemble nucleotide like sequences of DNA (deoxyribonucleic acid). They are mainly used in the treatment of cancer by inhibiting the enzyme reverse transcriptase. Moreover, they are used as antiviral drug; for instance, nucleotides analogs are AZT (azidothymidine) and ddI.
Additionally, nucleotide analogs are carcinogenic; they are incorporated into DNA molecule and cause base pair mismatches, which will synthesis mutations in the new DNA strand sequences.
Therefore, they block the DNA replication by preventing further elongation of strand that contains them. It results in inability to replicate and prevent the continued growth of cancer.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 6FB
In general, inducible operons are inactive until the substrate of their genes polypeptides is present.
Operons can be repressible or inducible. Repressible operon is the operon that is active unless a repressor molecule inhibits it. Inducible operon is the operon that is switched off, but is induced by a small molecule.
In inducible operon, regulatory repressor protein is bound to the operator that ceases the transcription. It is switched off when inducer (chemical) is present.
If inducer molecule is present it binds to the repressor, so repressor does not bind to the operator. It leads to the expression of the operon. Lac operon is example of inducible operon.
Hence, the correct answer is inducible operon.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 6MC
DNA polymerase III is functions as a proofreader for newly replicated strand of DNA (deoxyribonucleic acid) .
a) DNA polymerase III:
DNA polymerase III is a holoenzyme and it is involved in the prokaryotic replication. It contains two DNA polymerase embedded in a particle with nine other subunits.
The main function of DNA polymerase III is proofreader for newly replicated strand of DNA. Hence, this option is correct.
b) Primase:
It is an enzyme involved in DNA replication. It plays very important role in the DNA replication. It produces short RNA (ribonucleic acid) or DNA segment in some organisms is known as primer. In bacteria it binds to the DNA helicase and forms primosome. Hence, this option is incorrect.
c) Helicase:
It is a class of enzyme which is important to all living organisms. They play important function is to unpackaged the genes of organisms. Hence, this option is incorrect.
d) Ligase:
it is an enzyme which catalyzes the joining of two large molecules by forming a chemical bond. Hence, this option is incorrect.
Hence, the correct option is (a) DNA polymerase which functions as a proof reader for newly replicated strand of DNA.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 6SA
Components and structure of DNA and RNA in prokaryotes:
Explanation
Prokaryotic cells lack nucleus and do not having organelles. The DNA (deoxyribonucleic acid) contains only one chromosome. Moreover, the cells lack membrane bound nucleus and most of them are unicellular organisms. In prokaryotes DNA is located in the nucleoid and is spread throughout the entire cell.
Additionally, the transfer of DNA in prokaryotes is through transduction, conjugation, and transformation. Prokaryotic chromosomes have circular shape and have few proteins. They contain small circular DNA that replicate independently, known as plasmids.
Furthermore, prokaryotes contain large RNA (protein). RNA (mRNA) is immediately translated by ribosomes in to proteins. Larger subunit of the ribosomal RNA has 50 Svedberg units (50S) in molecular size and smaller subunit has 30 S in molecular size. These subunits join together to form protein factory. Thus, these are the main difference between prokaryotic DNA and RNA.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 7CT
DNA polymerase:
Explanation
DNA polymerase is a cellular polymerase enzyme. They produce DNA (deoxyribonucleic acid) molecules from the nucleotide building blocks. Moreover, plays an important role in the DNA replication, repair, genetic recombination, and reverse transcriptase. It is mainly used in molecular biology, DNA sequencing, and molecular cloning. Besides, it reads DNA strand in replication process and create another strand. It also helps in the production and catalyzes the bonds between nucleic acids in DNA.
Thus, DNA refers to deoxyribonucleic acid. It denotes the genetic makeup and -ase refers to enzyme or protein. Hence, DNA is named as DNA polymerase.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 7FB
A daughter DNA molecule is composed of one original strand and one new strand because DNA replication is semi conservative.
In DNA replication two strands of complementary DNA separates in to two original strands.
Each strand uses as a template for the synthesis of new complementary strand, so the DNA replication is semi conservative. It contains half original strand and half new strand.
Semi conservative replication was confirmed by the Meselson-Stahl experiment.
Hence, the correct answer is semi conservative.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 7MC
The methyl group addition to cytosine of DNA (deoxyribonucleic acid) is known as methylation.
a) Methylation:
Addition of the methyl group to cytosine of deoxyribonucleic acid is known as methylation. It modifies the expression of gene in the cells.
It removed in the zygote formation and reestablished in the cell divisions. It modifies which regulate gene expression. Moreover, it suppresses harmful stretches of deoxyribonucleic acid and the expression of endogenous retroviral genes. It forms bases of chromatin structure.
It plays very important role in the development of all types of cancer. Hence, this option is correct.
b) Restriction:
Restriction enzyme is used for the cutting DNA at specific recognition nucleotide sequence. It is also known as restriction endonuclease. They are mainly used for the DNA modification and manipulation. Hence, this option is incorrect.
c) Transcription:
It is first step of the gene expression. In this process DNA segment is copied into RNA (ribonucleic acid) polymerase. Hence, this option is incorrect.
d) Transversion:
The substation of purines for pyrimidines is known as transversion. It can be caused by the ionizing radiation. Hence, this option is incorrect.
Hence, the correct option is (a) methylation addition of the methyl group to the cytosine of the deoxyribonucleic acid.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 7SA
Difference in function of RNA polymerase with DNA polymerase:
Explanation
DNA (deoxyribonucleic acid) polymerase plays an important role in the replication process, but it is not capable of initiating, whereas RNA (ribonucleic acid) polymerase has the capability of initiation. Thymine base is present in DNA, whereas uracil base is present in RNA. RNA is single stranded, whereas DNA is double stranded. In addition, DNA polymerase requires RNA primer for initiating replication, but RNA polymerase does not require any primer.
RNA polymerase does not require helicase enzyme to unwind the DNA strands, whereas DNA require helicase enzyme for replication process. Moreover, RNA polymerase is capable of many functions on comparing with DNA polymerase. DNA polymerase starts function at 3’ end. RNA polymerase functions anywhere of the DNA strand, 3’ end to 5’ end direction.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 8CT
Effect of Corynebacterium diphtheria on cellular metabolism:
Explanation
Corynebacterium diphtheriae is gram positive bacteria. They mainly cause disease known as diphtheria. The bacteria produce a toxin called as diphtheria toxin. The toxin supports in the alteration of protein function in the host by inactivating the elongation factor (EF-2). Moreover, it slowly shows immediate toxic effect on the cell, because cell requires the productions of proteins continuously. Thus, there is no long term effect because cell is already dead.
Hence, Corynebacterium diphtheria secretes a toxin, which inactivates elongation factors of eukaryotic cell.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 8FB
A gene for antibiotic resistance can move horizontally among bacterial cells by transformation, transduction and bacterial conjugation.
Insertion of genetic material into the non-bacterial cells is known as transformation. It was demonstrated by the Frederick Griffith in 1928 in Streptococcus pneumoniae.
Injection of foreign DNA (deoxyribonucleic acid) by bacteriophage virus in to the host bacterium is known as transduction.
Transfer of genetic material between two bacterial cells through direct contact is known as conjugation.
By the process of transformation, transduction and bacterial conjugation antibiotic resistance can move among bacterial cells.
Hence, the correct answer is transformation, transduction and bacterial conjugation.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 8MC
In translation the binding site through which tRNA (transfer ribonucleic acid) molecules leave is known as E site.
a) A site:
Translation is a process that cellular ribosomes produce proteins and also synthesis polypeptides. It is a part of gene expression.
It complete in four process they are; initiation, elongation, translocation and termination. In this process the binding site through which tRNA (transfer ribonucleic acid) molecules leave is known as E site.
A site is accommodates a tRNA delivering an amino acid. Hence, this option is incorrect.
b) X site:
Translation is a process that cellular ribosomes produce proteins and also synthesis polypeptides. It is a part of gene expression.
It complete in four process they are; initiation, elongation, translocation and termination. In this process the binding site through which tRNA (transfer ribonucleic acid) molecules leave is known as E site. Hence, this option is incorrect.
c) P site:
Translation is a process that cellular ribosomes produce proteins and also synthesis polypeptides. It is a part of gene expression.
It complete in four process they are; initiation, elongation, translocation and termination. In this process the binding site through which tRNA (transfer ribonucleic acid) molecules leave is known as E site.
P site is holds a tRNA and the growing polypeptide. Hence, this option is incorrect.
d) E site:
Translation is a process that cellular ribosomes produce proteins and also synthesis polypeptides. It is a part of gene expression.
It complete in four process they are; initiation, elongation, translocation and termination. In this process the binding site through which tRNA (transfer ribonucleic acid) molecules leave is known as E site. In this site tRNA is exist. Hence, this option is correct.
Hence, the correct option is (d) E site which is the binding site of the tRNA molecules.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 8SA
Function and formation of mRNA, rRNA, and tRNA in eukaryotes and prokaryotes:
Explanation
The mRNA (messenger RNA) is large family of the RNA and it transmits genetic information from DNA (deoxyribonucleic acid) to the ribosome. In eukaryotes, translation occurs in ribosomes. Translation is not directly coupled to the transcription. In eukaryotes mRNA contains only one polypeptide.
Similarly, in prokaryotes mRNA is translated into proteins. The mRNA does not require processing or transported. Transcription immediately begins after the end of transcription. In prokaryotes translation is coupled to the transcription. Besides, eukaryotic and prokaryotic mRNA involves in transcription, transport, and translation. Main function of mRNA is to carry genetic information.
Additionally, rRNA (ribosomal RNA) is RNA, component of the ribosome. It is important in the protein synthesis of living organism. Prokaryotes contain 30S small subunit and 50S large subunit. In eukaryotes 28S, 5.8S, 18S, and 5S subunits of four types of cytoplasmic rRNA and 12S and 16S two types of subunits in mitochondria.
Furthermore, tRNA plays important role to translate the code words in mRNA. Each specific tRNA molecule contains three base sequences, which base pair with complimentary mRNA. It is specific to amino acid specific, scans and detects mRNA. Its structure resembles with clover leaf and has several extended loops. Thus, acts as tool in the translation process of mRNA.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 9CT
Use of siRNA to turn off a cancer-inducing gene:
Explanation
Small or short interfering RNA (siRNA) belong to a class of double stranded RNA molecules. It plays important role in the RNA (ribonucleic acid) interference path way and post transcriptional gene silencing. Moreover, they are used as a tool in validating gene function and drug targeting of post genome.
In addition, they are used in the turn off of cancerous cells, to produce specific proteins that make them differ from the normal cells. Scientists use this technique to cease the process, which converts a normal cell to cancerous cell from the beginning.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 9FB
Transposons are nucleotide sequences containing palindromes and genes for protein that cut DNA (deoxyribonucleic acid) strands.
Transposons are DNA segments of 700-40,000 bp in length that can move from one place to another place within the genome.
They were discovered by the American scientist McClintock in 1902-1992. They are also known as jumping genes. The action of the transposons is known as transposition. It occurs between the chromosomes and the plasmids. They transfer transposons from one cell to another cell.
Hence, the correct answer is transposons.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 9MC
Ames test is used for the auxotroph and liver extract to reveal potential mutagens.
a) Used auxotroph and liver extract to reveal potential mutagens:
Ames test is mainly used for strains of bacteria such as Salmonella typhimurium which carries mutations in gene involved in production of histidine.
These are autotrophic mutants they require histidine for growth. This test is mainly used for the auxotroph and liver extract to reveal potential mutagens.
A positive test indicates that the chemical is mutagenic and carcinogenic. Hence, this option is correct.
b) Is time intensive and costly:
Ames test is mainly used for strains of bacteria such as Salmonella typhimurium which carries mutations in gene involved in production of histidine. Hence, this option is incorrect.
c) Involves the isolation of a mutant by eliminating wild-type phenotypes with specific media:
Ames test is mainly used for strains of bacteria such as Salmonella typhimurium which carries mutations in gene involved in production of histidine. Hence, this option is incorrect.
d) Proves that suspected chemicals are carcinogenic:
Ames test is mainly used for strains of bacteria such as Salmonella typhimurium which carries mutations in gene involved in production of histidine. Hence, this option is incorrect.
Hence, the correct option is (a) uses auxotroph and liver extract to reveal potential mutagens which is known as Ames test.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 9SA
Package of DNA in prokaryotes and eukaryotes:
Explanation
DNA (deoxyribonucleic acid) is a double stranded helical structure. Moreover, it is a molecule that encodes genetic instructions for developing and functioning.
Similarly, it was identified by the Friedrich Miescher and its structure was predicted by the James Watson and Francis Crick. The structure of DNA contains four bases, which contains are adenine (A), cytosine (C), guanine (G), and thymine (T). It is used in the genetic engineering, bioinformatics, and DNA nanotechnology.
Additionally, eukaryotic, DNA is wrapped around the proteins known as histones. DNA is present within the nucleus. In this genetic material is condensed as linear and linear chromosome.
In prokaryotes DNA is compacted by the basic proteins known as histone like proteins. Genetic material is found in covalently circular form.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 10CT
Nucleotide analogs are useful to cancer research:
Explanation
Nucleotide analogs resemble nucleotide like sequences of DNA (deoxyribonucleic acid). They are mainly used in the treatment of cancer by inhibiting the enzyme reverse transcriptase. Moreover, they are used as antiviral drug; for instance, nucleotides analogs are AZT (azidothymidine) and ddI. Additionally, nucleotide analogs are carcinogenic; they are incorporated into DNA molecule and cause base pair mismatches, which will synthesis mutations in the new DNA strand sequences.
Additionally, they block DNA replication by preventing elongation of strand. It results in inability to replicate and prevent the continued growth of cancer. In contrast, they are active in the native form and work in the cells to activate phosphorylation by the drug. It clearly shows that they can act against HIV in infected cells.
Furthermore, they break DNA replication cells undergoing mitosis, which is a character of cancer cells. It leads to the cell to undergo apoptosis and later die. It is a useful method to kill cancer cells to avoid damage to normal cells.
Thus, in this way nucleotide analogs are useful to cancer researcher.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 10FB
Crossing over is a recombination event that occurs during gamete formation in eukaryotes.
Exchange of chromosomal segments between two non-sisters chromatids is known as crossing over. It is a reciprocal recombination that that involves in breaking and exchange between two nonsister chromatids. It occurs in prophase-I of meiosis. It provides genetic variation during meiosis.
Hence, the correct answer is crossing over.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 10MC
DNA (deoxyribonucleic acid) repair involves enzymes that recognize and a correct nucleotide error in unmethylated strands of DNA is known as mismatch repair.
a) Light repair of thymine dimers:
A cell identifies and corrects damage of DNA molecule which codes genome if known as DNA repair. U.V light and radiation of environmental factors cause DNA repair and some other lesions also cause mutations in cell.
Thymine dimers repaired by the two mechanisms photoreactivation repair and excision repair. Hence, this option is incorrect.
b) Dark repair of pyrimidines dimers:
A cell identifies and corrects damage of DNA molecule which codes genome if known as DNA repair. U.V light and radiation of environmental factors cause DNA repair and some other lesions also cause mutations in cell.
Pyrimidines dimers can be repaired by the photoreactivation or nucleotide excision repair. This type of repair mainly causes the melanomas in humans. Hence, this option is incorrect.
c) Mismatch repair:
A cell identifies and corrects damage of DNA molecule which codes genome if known as DNA repair. U.V light and radiation of environmental factors cause DNA repair and some other lesions also cause mutations in cell.
DNA repair involves enzymes that recognize and a correct nucleotide error in unmethylated strands of DNA is known as mismatch repair. Hence, this option is correct.
d) SOS response:
A cell identifies and corrects damage of DNA molecule which codes genome if known as DNA repair. U.V light and radiation of environmental factors cause DNA repair and some other lesions also cause mutations in cell.
The cell cycle is arrested and DNA repair and mutagens are induced is known as SOS response. In this process RecA protein is involved, it is produced by the single stranded DNA. Hence, this option is incorrect.
Hence, the correct option is (c) mismatch repair which is involves enzymes that recognize and a correct nucleotide error in unmethylated strands of DNA.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 10SA
Central dogma of genetics:
Explanation
Central dogma of the genetics is first coined by the Francis Crick in 1958. It explains flow of genetic information in biological system, which involves from DNA (deoxyribonucleic acid) to RNA (ribonucleic acid) and finally to protein.
Moreover, DNA carries genetic information and transcript to RNA. Then forms mRNA molecules carry amino acid sequence for protein synthesis.
Additionally, it forms the basis of storage, transmission, and expression of hereditary information. It is mainly divided into three groups, which are replication, translation and transcription.
Therefore, DNA copied into DNA is known as replication. DNA can be copied into mRNA, mediated by the process of transcription. In translation proteins are produced by using mRNA, as a template.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 11FB
Transfer RNA, its conformation studies:
Explanation
An adaptor molecule is composed of RNA (ribonucleic acid) and is known as tRNA. It contains 73 to 94 nucleotides in length. They are small RNA molecules. Moreover, they are important component in protein translation and production of new proteins. However, contains primary, secondary, and tertiary structure.
Similarly, tRNA is visualized as cloverleaf structure (3-D L shaped structure), which allows to P and A sites of the ribosomes. Whereas, in eukaryotes tRNA as transcribed by the RNA polymerase-3. They carry amino acids to organelles of the cell by ribosomes.
Thus, transfer RNA carries amino acids.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 11MC
The natural mechanism of genetic transfer and recombination is transduction, transformation and conjugation.
a) Transduction:
Insertion of foreign DNA (deoxyribonucleic acid) through a bacteriophage virus into the host bacterium is known as transduction. It needs physical contact between cells.
It plays important role in introducing foreign DNA in to host cell genome. Viruses which infect bacteria are known as bacteriophage. When bacteriophages to the bacterial cell.
It explains mechanism of antibiotic drugs become infective by the transfer of antibiotic resistance genes of bacteria. Hence, this option is incorrect.
b) Transformation:
Genetic alteration of a cell. It results from direct uptake, incorporation and expression of exogenous genetic material from its surrounding is known as transformation.
Some species of bacteria transformation occurs. It is also known as insertion of genetic material in to nonbacterial cells. It also used for the animals and plant cells.
It was demonstrated by the Frederick Griffith in 1928. It main principle is heat killed strain was responsible for producing harm less strain virulent. Hence, this option is incorrect.
c) Transcription:
It is first step of the gene expression. In this process DNA segment is copied into RNA (ribonucleic acid) polymerase. It is not a natural genetic mechanism and recombination mechanism. Hence, this option is correct.
d) Conjugation:
Transfer of genetic material between two bacterial cells through direct contact is known as conjugation. It was discovered by Joshua Lederberg and Edward Tatum in 1946
It is a horizontal gene transfer mechanism. In this process genetic element is plasmid or transposon
It was very important to transfer of antibiotic resistance and xenobiotic tolerance. Hence, this option is incorrect.
Hence, the correct option is (c) transcription which is not a mechanism of natural genetic transfer and recombination.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 11SA
Comparison and contrast between transformation, transduction, and conjugation:
Explanation
Transformation is the process of alteration of genetic information in the cell. It includes the uptake, integration, and exogenous genetic material from the surrounding; for instance, in few species of bacteria transformation. It includes the incorporation of genetic material into non-bacterial cells. It is used for the animals and plant cells. Moreover, it was demonstrated by the Frederick Griffith in 1928. The main principle lying behind is the strains of heat killed that are responsible in producing virulent, harmless strains.
Transduction is the insertion of foreign DNA into the host bacterium, through bacteriophage virus. It needs physical contact between cells. It plays an important role in introducing foreign DNA into host cell genome. Viruses, which infect bacteria, are known as bacteriophage. It explains mechanism of antibiotic drugs become infective by the transfer of antibiotic resistance genes of bacteria
Conjugation is the process of transferring genetic material between the two cells of bacteria through direct contact. It was discovered by Joshua Lederberg and Edward Tatum in 1946. Moreover, it the process of gene transfers mechanism that takes place horizontally. Thus, in this process genetic element is plasmid or transposon.
Hence, it is very important to transfer antibiotic resistance and xenobiotic tolerance.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 12FB
Sense and antisense RNA are complementary to nucleic acid molecule:
Explanation
Small interfering ribonucleic acid is also known as short interfering ribonucleic acid. In addition, small interfering ribonucleic acid is also called as silencing RNA, which plays an important role in post-transcriptional gene silencing of plants.
It encourages RNA interference in mammalian cells and plays a vital role in authorizing gene function and drug targeting of post genomic era. In addition, micro RNA is small non-coding macro molecule, which was found in plants and animals. It mainly involves in the transcriptional and post transcriptional gene expression.
Furthermore, the use of miRNA is complementary to a part of one or more messenger RNAs. It functions mainly in emerging of gene regulation.
Small interfering RNA (siRNA) and micro RNA (miRNA) are antisense; that is, they are complementary to another nucleic acid molecule.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 12MC
Cell which has the ability to take up extra cellular DNA (deoxyribonucleic acid) from their environment is known as competent cell.
a) Hfr cell:
High frequency recombinant cell (Hfr cell) is a bacterium. It is integrated with conjugative plasmid in to its genomic DNA. It was first discovered by the Luca Cavalla Sforza. Hence, this option is incorrect.
b) Genomic:
Genome of the entire organism is known as genomic cell. It encodes DNA or RNA. It includes both gene and RNA (ribonucleic acid)\ DNA non coding sequence. Hence, this option is incorrect.
c) Transposing:
DNA sequence change their position within the genome is known as transposing cells. It creates reversing mutations and changes the genome size of cell. Hence, this option is incorrect.
d) Competent:
Cell which has the ability to take up extra cellular DNA from their environment is known as competent cell. It was discovered by Frederick Griffith. It can be divided into natural competence and artificial competence. Hence, this option is correct.
Hence, the correct option is (d) competent which has ability to take up DNA from their environment.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 12SA
Replication is the process of DNA (deoxyribonucleic acid) by synthesizing two identical copies from the original DNA molecule.
Transcription is a gene expression. It is a particular segment of DNA that is copied into RNA (ribonucleic acid) by the RNA polymerase.
Translation is the process in cellular ribosomes to create proteins, which is responsible in producing polypeptides.
The following table depicts the filled blanks:
microbiology-with-diseases-by-taxonomy-chapter-7-answers-12sa

Microbiology with Diseases by Taxonomy Chapter 7 Answers 13MC
Transfer of genetic material between two bacterial cells through direct contact is known as conjugation.
a) Conjugation requires a sex pilus extending from the surface of a cell:
Transfer of genetic material between two bacterial cells through direct contact is known as conjugation. It was discovered by Joshua Lederberg and Edward Tatum in 1946
It is a horizontal gene transfer mechanism. In this process genetic element is plasmid or transposon
It requires a sex pilus extending from the surface of a cell. It was very important to transfer of antibiotic resistance and xenobiotic tolerance. Hence, this option is correct.
b) Conjugation involves a factor:
Transfer of genetic material between two bacterial cells through direct contact is known as conjugation. It was discovered by Joshua Lederberg and Edward Tatum in 1946
It is a horizontal gene transfer mechanism. In this process genetic element is plasmid or transposon
It requires a sex pilus extending from the surface of a cell. It was very important to transfer of antibiotic resistance and xenobiotic tolerance. Hence, this option is incorrect.
c) Conjugation is an artificial genetic engineering technique:
Transfer of genetic material between two bacterial cells through direct contact is known as conjugation. It was discovered by Joshua Lederberg and Edward Tatum in 1946
It is a horizontal gene transfer mechanism. In this process genetic element is plasmid or transposon
It requires a sex pilus extending from the surface of a cell. It was very important to transfer of antibiotic resistance and xenobiotic tolerance. Hence, this option is incorrect.
d) Conjugation involves DNA that has been released into the environment from dead organisms:
Transfer of genetic material between two bacterial cells through direct contact is known as conjugation. It was discovered by Joshua Lederberg and Edward Tatum in 1946
It is a horizontal gene transfer mechanism. In this process genetic element is plasmid or transposon
It requires a sex pilus extending from the surface of a cell. It was very important to transfer of antibiotic resistance and xenobiotic tolerance. Hence, this option is incorrect.
Hence, the correct option is (a) conjugation requires a sex pilus extending from the surface of a cell is known as conjugation.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 14MC
Segments of DNA (deoxyribonucleic acid) are known as transposons. It was discovered by the American scientist McClintock in 1902-1992. They are also known as jumping genes.
a) Hfr cell:
High frequency recombinant cell (Hfr cell) is a bacterium. It is integrated with conjugative plasmid in to its genomic DNA. It was first discovered by the Luca Cavalla Sforza. Hence, this option is incorrect.
b) Transducing phages:
They can able to bind bacterial cell and inject their contents. They have segment of bacterial DNA integrated into their genome. Hence, this option is incorrect.
c) Palindromic sequences:
It is a nucleotide sequence of DNA or RNA (ribonucleic acid). It read 5’-3’ on one strand and 3’-5’ direction of complementary strand. Hence, this option is incorrect.
d) Transposons:
Segments of DNA are known as transposons. They are 700-40,000 bp in length. They can move from one place to another place on the same molecule.
It was discovered by the American scientist McClintock in 1902-1992. They are also known as jumping genes. The action of the transposons is known as transposition.
Transposition was occurs between the chromosomes and the plasmids. They transfer transposons from one cell to another cell. Hence, this option is correct.
Hence, the correct option is (d) transposons which are also known as jumping genes.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 15MC
a) Crossing over of P and Q:
Exchange of genetic material between two homologous chromosomes is known as crossing over. It results in recombinant chromosomes. It was discovered by Thomas Hunt Morgan. Hence, this option is incorrect.
b) Vertical gene transfer:
The passing of the genes from the parent to the offspring is known as vertical gene transfer. It can be done by sexual or asexual. Hence, this option is incorrect.
c) Horizontal gene transfer:
Transfer of genes between organisms by using non-reproductive methods is known as horizontal gene transfer. In this process donor cell donate genome the recipient cell that varies species from the donor. It was rarely occur in the 1% of prokaryotes. Hence, this option is correct.
d) Transposition:
Transfer of genetic material between two organisms other than by vertical gene transfer is known as transposition. Hence, this option is incorrect.
Hence, the correct option is (c) horizontal gene transfer which is a non-reproductive method.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 16MC
A triplet nucleotide sequence in RNA (ribonucleic acid) is known as codon. It is a part of each molecule of mRNA (messenger RNA).
a) Palindrome:
Palindrome is word, number, phrase or element. Palindromic sequence is a nucleotide sequence of DNA (deoxyribonucleic acid) or RNA. It read 5’-3’ on one strand and 3’-5’ direction of complementary strand. Hence, this option is incorrect.
b) Anticodon:
It is a region of tRNA (transfer RNA). It is a sequence of three bases that are complementary to a codon in the mRNA (messenger RNA). Hence, this option is incorrect.
c) Codon:
The mRNA (messenger RNA) is large family of the RNA and it transmits genetic information from DNA to the ribosome.
It mainly involves in transcription, transport and translation. Important function of mRNA is carries genetic information.
The mRNA contains three groups of nucleotides; codon specifies the amino acid which makes up the protein. Hence, this option is correct.
d) Base pair:
Building blocks of the DNA double helix is known as base pair. It donates folded structure to the DNA and RNA. It maintains the helical structure of the DNA. Hence, this option is incorrect.
Hence, the correct option is (c) codon which is a part of each molecule of mRNA.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 17MC
Nucleotides are organic molecules which forms basic building blocks of the nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)
a) A five carbon sugar:
Nucleotides are used in the replication of DNA for caring energy. They are found in four forms, each with a deoxyribose sugar, a phosphate and a base.
They are present in the cytosol of the cells as triphosphate nucleotides. They are made up of three parts they are; five carbon sugar, nitrogenous base and phosphate. Hence, this option is correct.
b) Phosphate:
Nucleotides are used in the replication of DNA for caring energy. They are found in four forms, each with a deoxyribose sugar, a phosphate and a base.
They are present in the cytosol of the cells as triphosphate nucleotides. Nucleotides are made up of three parts they are; five carbon sugar, nitrogenous base and phosphate. Hence, this option is correct.
c) A nitrogenous base:
Nucleotides are used in the replication of DNA for caring energy. They are found in four forms, each with a deoxyribose sugar, a phosphate and a base.
They are present in the cytosol of the cells as triphosphate nucleotides. They are made up of three parts they are; five carbon sugar, nitrogenous base and phosphate. Hence, this option is correct.
d) All of the above:
Nucleotides are used in the replication of DNA for caring energy. They are found in four forms, each with a deoxyribose sugar, a phosphate and a base.
They are present in the cytosol of the cells as triphosphate nucleotides. They are made up of three parts they are; five carbon sugar, nitrogenous base and phosphate. Hence, this option is correct.
Hence, the correct option is (d) all of the above which are made up of three parts they are; five carbon sugar, nitrogenous base and phosphate

Microbiology with Diseases by Taxonomy Chapter 7 Answers 18MC
In DNA (deoxyribonucleic acid) adenine forms two hydrogen bonds with thymine.
a) Three/uracil:
Hydrogen bonding is a chemical reaction. In DNA adenine, guanine, cytosine and thymine are nitrogen bases.
They are bonded with various number of hydrogen. In DNA adenine forms two hydrogen bonds with thymine. Hence, this option is incorrect.
b) Two/uracil:
Hydrogen bonding is a chemical reaction. In DNA adenine, guanine, cytosine and thymine are nitrogen bases.
They are bonded with various number of hydrogen. In DNA adenine forms two hydrogen bonds with thymine. Hence, this option is incorrect.
c) Two/thymine:
Hydrogen bonding is a chemical reaction. In DNA adenine, guanine, cytosine and thymine are nitrogen bases.
They are bonded with various number of hydrogen. In DNA adenine forms two hydrogen bonds with thymine. Hence, this option is correct.
d) Tree/ thymine:
Hydrogen bonding is a chemical reaction. In DNA adenine, guanine, cytosine and thymine are nitrogen bases.
They are bonded with various number of hydrogen. In DNA adenine forms two hydrogen bonds with thymine. Hence, this option is incorrect.
Hence, the correct option is (c) two/thymine which is formed by the DNA, adenine.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 19MC
A sequence of nucleotides formed during replication of the lagging DNA (deoxyribonucleic acid) strand is known as an Okazaki fragments.
a) A palindrome:
Palindrome is word, number, phrase or element. Palindromic sequence is a nucleotide sequence of DNA or RNA (ribonucleic acid). It read 5’-3’ on one strand and 3’-5’ direction of complementary strand. Hence, this option is incorrect.
b) An Okazaki fragment:
They are short, newly produced DNA fragments. They formed lagging template strand in DNA replication. They are complimentary to the lagging template strand. They are 1000 to 2000 nucleotides long. Hence, this option is correct.
c)A template strand:
It is mainly used in the synthesis mRNA. It is used to describe DNA strands. It is a sequence of the DNA that is copied in mRNA (messenger RNA) synthesis.
Hence, this option is incorrect.
d) An operon:
Operon is functioning unit of the genomic DNA. It is related to regulons, stimulons and modulons.
It was discovered by the Jacob and Jacques Monod. Operon has three parts operator, promoter and repressor.
They exist in both prokaryotes and eukaryotes. They are also found in viruses like bacteriophages. It regulates the gene expression. Hence, this option is incorrect.
Hence, the correct option is (b) an Okazaki fragment which is a sequence of nucleotides formed during replication of the lagging DNA strand.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 20MC
Operon is functioning unit of the genomic DNA (deoxyribonucleic acid). It is related to regulons, stimulons and modulons. It was discovered by the Jacob and Jacques Monod. Operon has three parts operator, promoter and repressor.
a) Operator:
Operator is a segment of the DNA, which is regulator binding. It is defined as segment between promoter and the series of genes. Hence, this option is incorrect.
b) Promoter:
Promoter is a nucleotide sequence. It allows the gene transcription. It was recognized by RNA (ribonucleic acid) polymerase. It indicates which gene used for the mRNA (messenger RNA) in RNA production. Hence, this option is incorrect.
c) Origin:
It is a point of where is something starts or created. It is not a part of operon. Hence, this option is correct.
d) Gene:
Gene is co-regulated by the operon. It codes the enzymes in metabolic pathway. Hence, this option is incorrect.
Hence, the correct option is (c) origin which is a not a part of operon.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 21MC
RNA (ribonucleic acid) transcription is responsible for the operons are important in regulation prokaryotic.
a) DNA replication:
It is a process of synthesizing two identical copies from original strand of DNA (deoxyribonucleic acid) is knows as DNA replication. Hence, this option is incorrect.
b) RNA transcription:
It is first step of gene expression. It is a segment of DNA that is copied into the RNA by the enzyme RNA polymerase. In RNA transcription operons are important in regulation. Hence, this option is correct.
c) Ribosomal RNA (rRNA) processing:
It is synthesized from large transcript (pre rRNA) which under goes cleavage of both ends of the transcript. Hence, this option is incorrect.
d) Sugar metabolism:
Sugar is metabolized by the all organisms. They are stored as long polymers of the glucose molecules with glucosidic bonds. It gives structural support and energy storage. Hence, this option is incorrect.
Hence, the correct option is (b) RNA transcription which is responsible for the operons are important in regulation prokaryotic.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 22MC
Transcription is first step of the gene expression. It produces RNA (ribonucleic acid) molecules.
a) DNA molecules:
DNA (deoxyribonucleic acid) is molecule encodes genetic instructions for developing and functioning. It is double stranded helical structure.
It was identified by the Friedrich Miescher and its structure was predicted by the James Watson and Francis Crick.
It contains four bases; they are adenine (A), guanine (G), cytosine (C) and thymine (T). It was used in the genetic engineering, bioinformatics and DNA nanotechnology. Hence, this option is incorrect.
b) RNA molecules:
They are large biological molecule. They plays important role in coding, decoding, regulation and gene expression.
They catalyze biological reactions and control gene expression. They are produced by the transcription process.
Transcription is first step of the gene expression. In this process DNA segment is copied into RNA polymerase. Hence, this option is correct.
c) Polypeptides:
Polypeptides are short chains of amino acids that are linked by the peptide bonds. They are long, continuous and unbranched peptide chain. Hence, this option is incorrect.
d) Palindromes:
Palindrome is word, number, phrase or element. Palindromic sequence is a nucleotide sequence of DNA or RNA. It read 5’-3’ on one strand and 3’-5’ direction of complementary strand. Hence, this option is incorrect.
Hence, the correct option is (b) RNA molecules which are produced by the transcription process.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 23MC
Ligase plays a major role in the lagging strand replication.
a) Lagging strand replication:
Ligase is a specific type of enzyme. It plays important role in the joining of DNA (deoxyribonucleic acid) strands together by forming phosphodiester bonds. It plays very important role in the lagging strand replication.
It plays important role in repairing single stranded breaks in the DNA. It also use in gene cloning. Hence, this option is correct.
b) Messenger RNA (mRNA) processing in eukaryotes:
Eukaryotic mRNA has only one site for initiation and termination of the protein synthesis, where as in eukaryotes mRNA is monocistronic.
In eukaryotes mRNA is synthesized from DNA template. Therefore in prokaryotes mRNA is still being transcribed from the DNA molecule. Hence, this option is incorrect.
c) Polypeptide synthesis by ribosome:
Polypeptides are short chains of amino acids that are linked by the peptide bonds. They are long, continuous and unbranched peptide chain. Hence, this option is incorrect.
d) RNA transcription:
It is first step of gene expression. It is a segment of DNA that is copied into the RNA (ribonucleic acid) by the enzyme RNA polymerase. In RNA transcription operons are important in regulation. Hence, this option is incorrect.
Hence, the correct option is (a) lagging strand replication which is an important role of ligase.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 24MC
Change of genome of nucleotide sequence of genome of an organism is known as mutation. They cause unrepaired damage to the DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) genomes.
a) Lasting:
Change of genome of nucleotide sequence of genome of an organism is known as mutation. They cause unrepaired damage to the DNA and RNA genomes.
They play vital role in the normal and abnormal biological process. They can the sequences. They also occur in the nongenic regions.
Before mutations can affect the population permanently they must be lasting, inheritable and beneficial. Hence, this option is correct.
b) Inheritable:
Change of genome of nucleotide sequence of genome of an organism is known as mutation. They cause unrepaired damage to the DNA and RNA genomes.
They play vital role in the normal and abnormal biological process. They can the sequences. They also occur in the nongenic regions.
Before mutations can affect the population permanently they must be lasting, inheritable and beneficial. Hence, this option is correct.
c) Beneficial:
Change of genome of nucleotide sequence of genome of an organism is known as mutation. They cause unrepaired damage to the DNA and RNA genomes.
They play vital role in the normal and abnormal biological process. They can the sequences. They also occur in the nongenic regions.
Before mutations can affect the population permanently they must be lasting, inheritable and beneficial. Hence, this option is correct.
d) All of the above:
Change of genome of nucleotide sequence of genome of an organism is known as mutation. They cause unrepaired damage to the DNA and RNA genomes.
They play vital role in the normal and abnormal biological process. They can the sequences. They also occur in the nongenic regions.
Before mutations can affect the population permanently they must be lasting, inheritable and beneficial. Hence, this option is correct.
Hence, the correct option is (c) all of the above which is before mutations can affect the population permanently they must be lasting, inheritable and beneficial.

Microbiology with Diseases by Taxonomy Chapter 7 Answers 25MC
A group of genes which are used together for synthesis of tryptophan is known as tryptophan operon. It was present in the bacteria. It regulates when tryptophan is present in the environment.
a) Active/an inducer:
A group of genes which are used together for synthesis of tryptophan is known as tryptophan operon. It was discovered by the Jacques Monod in 1953.
It was present in the bacteria. It regulates when tryptophan is present in the environment.
They are repressible that means they are active and directly controlled by a repressor. Hence, this option is incorrect.
b) Active/ a repressor:
A group of genes which are used together for synthesis of tryptophan is known as tryptophan operon. It was discovered by the Jacques Monod in 1953.
It was present in the bacteria. It regulates when tryptophan is present in the environment.
They are repressible that means they are active and directly controlled by a repressor. Hence, this option is correct.
c) Inactive/an inducer:
A group of genes which are used together for synthesis of tryptophan is known as tryptophan operon. It was discovered by the Jacques Monod in 1953.
It was present in the bacteria. It regulates when tryptophan is present in the environment.
They are repressible that means they are active and directly controlled by a repressor. Hence, this option is incorrect.
d) Inactive/a repressor:
A group of genes which are used together for synthesis of tryptophan is known as tryptophan operon. It was discovered by the Jacques Monod in 1953.
It was present in the bacteria. It regulates when tryptophan is present in the environment.
They are repressible that means they are active and directly controlled by a repressor. Hence, this option is incorrect.
Hence, the correct option is (b) active/a repressor which is function of the tryptophan operon.