Frank Solutions for Chapter 10 Respiration in Plants Class 9 Biology ICSE


1. Answer the following:
(a) What do you understand by respiration?
(b) What are the respiratory substrates? Give two examples.
(c) Write the overall equation of aerobic respiration.
(d) What is alcoholic fermentation?
(e) Which process is common to aerobic and anaerobic respiration?
(f) Where does glycolysis take place in the living cell?
(g) Name the cell organelle in which Kreb's take place.
(a) Respiration is the process of oxidation and decomposition of organic compounds like simple carbohydrate glucose in the living cells with the release of energy.
(b) Respiratory substrate is a substance which is oxidized to yield energy necessary for cell maintenance and growth. example- carbohydrates and fats.
(c) C6H12O6 + 6O2 → 6CO2 + H2O + 673 kcal energy (38 ATP)
(d) Alcoholic fermentation is a biological process in which hexose sugars such as glucose and fructose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products.
(e) Glycolysis
(f) Cytoplasm of cell
(g) Mitochondria

2. Distinguish between:
(a) Fermentation and anaerobic respiration.
(b) Aerobic respiration and anaerobic respiration.
(c) Respiration and combustion.
(a) Difference between Fermentation and anaerobic respiration
Fermentation Anaerobic respiration
It occurs in microorganisms and yeast It occurs in higher plants

(b) Difference between Aerobic respiration and anaerobic respiration

Aerobic respiration Anaerobic respiration
Occurs in presence of oxygen Occurs in absence of oxygen
Complete oxidation of glucose takes place  Incomplete oxidation of glucose takes place
More energy is liberated  Less energy is liberated
End-products are water and carbon dioxide  End-products are ethyl alcohol and carbon dioxide
It takes place in cytoplasm and mitochondria All the actions occur in cytoplasm

(c) Difference between Respiration and combustion

Respiration Combustion
It takes place in living cells only It does not occur in living cells only
Food material is oxidized stepwise, accompained with stepwise release of energy The substrate is oxidized at random and energy is released from the spontaneous breakdown of foodstuff
Most of the energy released is sorted in the form of ATP The energy released is lost in the form of light and heat
It is a continuous process It is not a continuous process

3. How will you demonstrate that energy is released during aerobic and anaerobic respiration?
Take two thermos flasks. In the first flask, keep some germinated seeds and a little water to 
keep them moist. In the second flask, keep some boiled seeds. Place corks fitted with thermometers on both the flasks. keep the flasks airtight. Note the temperature in both the thermometers. Leave the flasks for sometime and again record the temperature. 
It is observed that the temperature of the first set increases and in the second case, it is not affected. The rise in temperature is because during respiration, germinated seeds release some energy in the form of heat energy.

4. Do you agree that respiration is the reverse of photosynthesis?
Yes, respiration is the reverse of photosynthesis.

5. Match the terms of column A with the statements in column B:

Column A

Column B

(i) Yeast

(a) partial breakdown of food substance

(ii) Glucose

(b) nutrients are oxidized without using molecular oxygen by the process of fermentation

(iii) Anaerobic

(c) is the best organic substrate for respiration

(iv) Glycolysis

(d) The intermediate substance in the breakdown of glucose

(v) Pyruvic acid

(e) the series of change from glucose to pyruvic acid in respiration


Column A

Column B

(i) Yeast

(b) nutrients are oxidized without using molecular

(ii) Glucose

(c) is the best organic substrate for respiration.

(iii) Anaerobic

(a) partial breakdown of food substance.

(iv) Glycolysis

(e) the series of change from glucose to pyruvic acid in respiration.

(v) Pyruvic acid

(d) the intermediate substance in the breakdown of glucose.

6. Given alongside is an experiment setup to demonstrate a phenomenon in plant:
(a) What is the aim of this experiment?
(b) Why was the bell jar covered with black cloth?
(c) What is the function of caustic soda in this experiment?
(d) Give an overall chemical equation of the process mentioned in (a) above.
(e) Mention one precaution that should be taken to ensure more accurate results.
What change, if any, would you observe in the lime water in flask A and B? In each case give a reason for your answer.
(a) Aim - To show that carbon dioxide is released during respiration.
(b) To prevent photosynthesis
(c) To absorb carbon dioxide from incoming air
(d) C6H12O6 + 6O2 → 6CO2 + H2O + 673 kcal energy (38 ATP)
(e) The respiratory chamber should be covered with a black cloth to prevent photosynthesis.
The lime water in flask A turns milky as the plant respires and gives out carbon dioxide which turns the lime water milky. The lime water in flask B remains clear as the incoming air is free from carbon dioxide.

7. Fill in the blanks:
(a) Fermentation is a type of ______ respiration.
(b) The first phase of respiration is ______.
(c) ______ is the last product of glycolysis.
(d) The final hydrogen acceptor in aerobic respiration is ______.
(e) In living cells glycolysis occurs in ______.
(a) Anaerobic
(b) Glycolysis
(c) Pyruvic acid
(d) Oxygen
(e) Cytoplasm

8. Write True or False against each of the following statements:
(a) Combustion is a biological process.
(b) Kreb's cycle is common to both types of respiration.
(c) Glycolysis takes place in the crystal of the mitochondria.
(d) Protein is the first choice as a respiratory substrate.
(e) The respiration is faster than combustion.
(a) False
(b) False
(c) False
(d) False
(e) False

9. Moist germinated seeds were placed in a thermos flask A, and germinating seeds, which were boiled and then soaked in 5 per cent formalin, were placed in thermos flask B. Thermometers
were inserted in the flask and the mouth of each flask plugged with moist cotton wool. The two flasks were fixed upside down as shown in the fig. 10.9. The temperature on both thermometers was noted. After about 48 hours, the temperature in flask A was found to be much higher than that in flask B.
(a) State the object of using the apparatus
(b) Explain, why a rise in temperature occurs in flask A
(c) If 5 percent formalin was not used after boiling the seeds, the temperature of flask B would have risen considerably. Explain.
(a) To show that heat is evolved during respiration
(b) In flask A, moist seeds respire and produce heat that increases the temperature.
(c) If formalin was not used, bacteria will grow on the dry seeds and respire anaerobically to produce a little heat.

10. Complete the following statement by selecting the correct alternative from the ones given within brackets: The immediate source of energy for metabolic reactions in a living cell is ______.
(glucose ATP, protein)
glucose ATP

11. (a) Give the overall chemical equation that represents anaerobic respiration in plants.

(b) Mention any three points in which respiration is exactly opposite of photosynthesis.

(a) C6H12O6 → 2C2H5OH+ 2CO2 + 21 kcal energy (2 ATP)
Respiration Photosynthesis
Respiration is a catabolic process during which food material is broken down and energy is released Photosynthesis is an anabolic process during which food material is synthesized and energy is stored
The dry weight of plant decreases The dry weight of plant increases
Oxygen is used here Oxygen is released
Carbon dioxide is released Carbon dioxide is used up

12. The given fig. refers to an apparatus which is used to demonstrate a physiological process:
(a) What is the purpose of keeping potassium hydroxide solution in test tubes X and Y?
(b) What is the purpose of keeping boiled peas soaked in disinfectant in test tube Y?
(c) Why has coloured water risen in tube 1?
(d) Name the biological process which causes the above rise
(e) Define the biological process shown in the experiment
(a) To absorb carbon dioxide produced during respiration
(b) If these are not soaked in disinfectant, the bacterial growth may be there in the tube Y
and accurate result may not be obtained due to bacterial respiration.
(c) The germinating peas respire and oxygen is used which create a vacuum in the tube.
So, coloured water has risen in tube1.
(d) Respiration
(e) It is defined as the stepwise oxidation of glucose in the living cells to release energy.

13. Write scientific terms for the following:
(a) The power house of the cell.
(b) Anaerobic respiration in the muscles.
(a) mitochondria
(b) Fermentation

14. Differentiate between glycolysis and Kreb's cycle (reaction site of the process in a cell).
Difference between glycolysis and Kreb's cycle
Glycolysis Kerb's cycle
It occurs in both aerobic and anaerobic respiration It occurs only in aerobic respiration, but not in anaerobic respiration
It occurs in the cytoplasm of cell It occurs in mitochondria of cell

15. Differentiate between aerobic and anaerobic respiration (end-products of the process)
Difference between aerobic and anaerobic respiration
Aerobic respiration Anaerobic respiration
End-products are water and carbon dioxide. End-products are ethyl alcohol and carbon dioxide.

16. Complete the following statements by choosing the correct alternative out of those given within brackets.
(a) Every living cell of the plant (respire / photosynthesizes / as well as photosynthesizes).
(b) Normally, respiration takes place in (day / night / day and night).
(c) Carbon dioxide and water are formed in (photosynthesis / aerobic respiration / anaerobic respiration).
(d) In respiration, temperature (rises / comes down / remains the same).
(e) In respiration, energy is released in (controlled manner / uncontrolled manner / the form of light).
(a) Respires
(b) Day and night
(c) Aerobic respiration
(d) Rises
(e) Controlled manner

17. Name the following:
(a) The process of living beings which is concerned with the release of energy for use in the body.
(b) The energy currency of the body.
(c) The respiration that takes place in the presence of oxygen.
(d) The respiration takes place in the absence of oxygen.
(e) The chemicals generally used to absorb carbon dioxide in respiratory experiments.
(f) The solution that turns milky when carbon dioxide is passed through that solution.
(g) The products formed as a result of aerobic respiration.
(h) The products formed as a result of anaerobic respiration.
(a) Respiration
(b) ATP
(c) Aerobic respiration
(d) Anaerobic respiration
(e) Caustic potash and KOH
(f) Lime water
(g) Carbon dioxide and water
(h) Ethyl alcohol and carbon dioxide

18. Every question has four options. Choose the correct answer:

(i) In the process of respiration
(a) ADP is converted to ATP.
(b) Glucose is converted to carbon dioxide.
(c) Glucose is converted to carbon dioxide and water, releasing energy.
(d) Pyruvic acid is converted to ATP.
(c) Glucose is converted to carbon dioxide and water, releasing energy.

(ii) Which order is right for cellular respiration from the following
(a) Electron transfer, glycolysis, Kreb's cycle.
(b) Kreb's cycle, electron transfer, glycolysis.
(c) Electron transfer, Kreb's cycle, glycolysis.
(d) Glycolysis, Kreb's cycle, electron transfer.
(d) Glycolysis, Kreb’s cycle, electron transfer

(iii) Less energy is liberated in anaerobic respiration in yeast in comparison with aerobic respiration because
(a) Energy is not formed by oxygen.
(b) Less CO2 is formed.
(c) Energy is left in alcohol.
(d) Yeast requires less energy.
(c) Energy is left in alcohol.

(iv) The role of oxygen in cellular respiration
(a) To form CO2
(b) To liberate energy from hydrogen storage.
(c) To change pyruvate into acetyl CoA.
(d) To accept hydrogen and form water.
(d) To accept hydrogen and form water.

(v) The materials formed in anaerobic respiration are
(a) CO2 and water
(b) CO2 and alcohol
(c) CO2 and formaldehyde
(d) CO2 and haemoglobin
(b) CO2 and alcohol

(vi) The reactions of Kerb's cycle occurs in
(a) Lysosomes
(b) grana
(c) Mitochondria
(d) endoplasmic reticulum
(c) mitochondria

(vii) Who discovered the Kreb's cycle?
(a) Kolliker
(b) Hens Krebs
(c) Altman
(d) Benda
(b) Hens Krebs

(viii) Alcohol is produced during the process of
(a) photosynthesis
(b) aerobic respiration
(c) combustion
(d) fermentation
(d) fermentation

(ix) The energy liberated during respiration is stored in the form of
(a) heat
(b) ATP
(c) ADP
(d) NADP
(b) ATP

(x) Mitochondria is the storage house for:
(a) NADH
(b) Pyruvic acid
(c) ATP
(d) Citric acid
(c) ATP

(xi) How many ATP molecules are gained in glycolysis?
(a) Zero
(b) Two
(c) Four
(d) Eight
(b) Two

(xii) Where does the glycolysis take place?
(a) In cytoplasm
(b) In chloroplast
(c) In ribosome
(d) In mitochondria
(a) In cytoplasm

(xiii) The energy liberated in aerobic respiration is
(a) 637 Kcal
(b) 600 Kcal
(c) 673 Kcal
(d) 693 Kcal
(c) 673 Kcal
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