{"id":19751,"date":"2018-02-01T09:48:32","date_gmt":"2018-02-01T09:48:32","guid":{"rendered":"https:\/\/cbselibrary.com\/?p=19751"},"modified":"2020-11-25T17:09:37","modified_gmt":"2020-11-25T11:39:37","slug":"cbse-class-10-science-lab-manual-co2-released-respiration","status":"publish","type":"post","link":"https:\/\/cbselibrary.com\/cbse-class-10-science-lab-manual-co2-released-respiration\/","title":{"rendered":"CBSE Class 10 Science Lab Manual – CO2 is Released During Respiration"},"content":{"rendered":"
Aim<\/strong><\/span> Theory\/Principle<\/strong><\/span> 1. Aerobic Respiration<\/strong> METHOD 1<\/strong><\/span><\/p>\n Materials Required<\/strong><\/span> Procedure<\/strong><\/span><\/p>\n Observation<\/strong><\/span> METHOD 2<\/strong><\/span><\/p>\n Materials Required<\/strong><\/span> Procedure<\/strong><\/span><\/p>\n Observation<\/strong><\/span> Result<\/strong><\/span> Precautions<\/strong><\/span> Viva – Voce<\/strong><\/span><\/p>\n Question 1.<\/span><\/strong> Question 2.<\/span><\/strong> Question 3.<\/span><\/strong> Question 4.<\/span><\/strong> Question 5.<\/span><\/strong> Question 6.<\/span><\/strong> Question 7.<\/span><\/strong> Question 8.<\/span><\/strong> Question 9.<\/span><\/strong> Question 10.<\/span><\/strong> Question 11.<\/span><\/strong> Question 12.<\/span><\/strong>
\nTo show that carbon dioxide is released during the process of respiration.<\/p>\n
\nPlants perform many physiologically important functions to survive like photosynthesis and respiration. Respiration is a catabolic process (as large molecules are broken down into smaller units) and may be defined as the process that liberates energy when organic molecules are oxidised.
\nRespiration is of two types:<\/p>\n\n
\nIt is the respiration process occurring in the presence of oxygen. A complete oxidation of glucose (carbohydrates) takes place releasing carbon dioxide gas, water and a large amount of energy in the form of ATP (i.e. adenosine triphosphate) during this process.
\nThe reaction of this process is represented by the following equation:
\n
\n2. Anaerobic Respiration<\/strong>
\nIt is the respiration process occurring in the absence of oxygen. It leads to incomplete oxidation of organic food (glucose) releasing carbon dioxide and ethyl alcohol and a very less\/insignificant amount of energy. It is more commonly called as fermentation in micro-organisms.
\nThe reaction of this process is represented by the following equation:
\n
\nIn this experiment to show that CO2<\/sub><\/em> is released during respiration, moist gram seeds are used as they are actively respiring and release CO2<\/sub><\/em>.
\nThe released CO2<\/sub><\/em> is absorbed by KOH and forms K2<\/sub><\/em>CO3<\/sub><\/em> (Method 1).
\n
\nAlso, CO2<\/sub><\/em> can cause lime water to change its appearance (Method 2).<\/p>\n
\nA conical flask, soaked and germinating seeds of gram, 20% freshly prepared KOH (potassium hydroxide) solution, vaseline, U-shaped delivery tube (a tube bent twice at right angles), moist cloth (cotton\/wool or moist blotting paper), water, thread, beaker, test tube and a rubber cork with one hole.<\/p>\n\n
\n<\/li>\n
\nAfter 2 hours, it was observed that the level of the water has risen up in the U-shaped delivery tube dipped in the beaker from the initial marked level (Fig. 2).
\nGerminating seeds in the conical flask release CO2<\/sub><\/em> during respiration which is absorbed by KOH kept in small tube. Due to the absorption of CO2<\/sub><\/em> a vacuum is created in the flask which causes the rise in level of water in the delivery tube.
\nAnother method can also be used to show that CO2<\/sub><\/em> releases during respiration by plants.
\n<\/p>\n
\nGerminating gram seeds, lime water or phenol red indicator, vaseline, a thistle funnel, a delivery tube, a rubber tubing, rubber cork with two holes, conical flask and a boiling tube.<\/p>\n\n
\n<\/li>\n
\nThe colour of phenol red indicator changes from pink (in neutral\/alkaline medium) to pale yellow (in acidic medium) due to the addition of carbon dioxide in it.<\/p>\n
\nThe germinating seeds of gram performs active respiration and release C02 which can be – seen as:<\/p>\n\n
\nThus, it is confirmed that respiration in plants releases CO2<\/sub><\/em>.<\/li>\n<\/ul>\n
\nGerminating seeds should be kept moist at all times.
\nAll the experiment setup connections must be air tight.
\nFreshly prepared KOH solution must be used. KOH is corrosive, handle it carefully
\nThe end of the delivery tube present in the beaker In both methods should be completely immersed in water\/lime water.
\nLime water should be freshly prepared for experimental use.<\/p>\n
\nWhat is the roie of KOH in this experiment (Method 1)? [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nThe KOH solution suspended in the flask absorbs the CO2<\/sub><\/em> released by germinating seeds.<\/p>\n
\nWhen we say that plants and animals respire, where exactly is the process occurring? [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nThe process of respiration occurs in the mitochondria of the cell.<\/p>\n
\nWhy do we use germinating seeds in this experiment (Method 1)? [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nGerminating seeds respires actively at a faster rate.<\/p>\n
\nWhy germinating seeds or flower buds are ideal materials for this experiment (Method 2)? [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nBecause their cells are active and they actively exchange the respiratory gases (CO2<\/sub><\/em> and O2<\/sub><\/em>) as the oxidation of food takes place in these cells.<\/p>\n
\nWhy is the experimental setup kept in sunlight in method 2? [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nTo make the rate of germination much faster.<\/p>\n
\nWhy do we pour water into the boiling tube containing germinating seeds through a thistle funnel? [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nThistle funnels are used to add small amount of liquids (water) to an exact position. Thus, water is poured through a thistle funnel into the boiling tube containing germinating seeds as water is required for germination.<\/p>\n
\nWhat is the gas that reacts with phenol red indicator (or with the lime water)? [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nCO2<\/sub><\/em><\/p>\n
\nHow do germinating seeds respire\u2014aerobically or anaerobically? Analyse. [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nGermination seeds respire aerobically. CO2<\/sub><\/em> is produced as an end product, when respiration occurs in the presence of oxygen.<\/p>\n
\nDrop a NaOH (or KOH) pellet into the pale yellow phenol red indicator and observe? Reason out the cause of the change. [NCERT]<\/strong>
\nAnswer:<\/strong><\/span>
\nPale yellow phenol red indicator (acidic medium) will turn into pink on addition with NaOH or KOH. As phenol red gives pink colour on addition of base.<\/p>\n
\nIn which form energy is produced and utilised in our body?
\nAnswer:<\/strong><\/span>
\nATP (Adenosine triphosphate).<\/p>\n
\nThe germinating seeds are required to be kept moist during the experiment. Why so?
\nAnswer:<\/strong><\/span>
\nGerminating seeds are in growing stage and require water. If water is not available, the seeds will dry up and rate of respiration will slow down.<\/p>\n
\nAerobic respiration is different from anaerobic respiration. How?
\nAnswer:
\n<\/strong><\/span><\/p>\n