Class 9 Respiration in Plants Mock Test (ICSE)

Topics in Respiration in Plants

• Aerobic and anaerobic respiration
• Experiments on respiration
• Respiration and photosynthesis compared
• Factors affecting respiration

Respiration in Plants practice questions with answers

1. Q1Multiple choice·1 mark
   The optimum temperature range for the maximum rate of respiration in most living plant tissues is:

   1. (a)$0^\circ\text{C}$ to $10^\circ\text{C}$
   2. (b)$45^\circ\text{C}$ to $60^\circ\text{C}$
   3. (c)$75^\circ\text{C}$ to $90^\circ\text{C}$
   4. (d)$20^\circ\text{C}$ to $35^\circ\text{C}$
   Show answer and step marks

   1. Correct option: (d)+1

   Answer: (d)
2. Q2Multiple choice·1 mark
   In the experiment to demonstrate that heat is evolved during germination of seeds, a thermos flask is used because:

   1. (a)it supplies external heat to accelerate seed germination.
   2. (b)it provides an airtight medium that deprives seeds of oxygen.
   3. (c)it absorbs the carbon dioxide released during respiration.
   4. (d)it prevents the loss of metabolic heat generated by the seeds to the surroundings.
   Show answer and step marks

   1. Correct option: (d)+1

   Answer: (d)
3. Q3Multiple choice·1 mark
   Which of the following statements is true regarding the occurrence of photosynthesis and respiration in green plants during a 24-hour cycle?

   1. (a)Respiration goes on day and night, but photosynthesis needs light
   2. (b)Photosynthesis occurs by day, and respiration takes its place at night
   3. (c)Both processes occur in light, and both stop during the night
   4. (d)Both processes occur day and night at the same steady rate
   Show answer and step marks

   1. Correct option: (a) Respiration goes on day and night, but photosynthesis needs light. Every living cell respires all the time, while photosynthesis stops in the dark.+1

   Answer: (a)
4. Q4Short answer·2 marks
   Give a scientific reason for the following: In the experiment set up with germinating seeds to study aerobic respiration, a small test tube containing caustic potash ($\text{KOH}$) solution is hung inside the conical flask.
   Show answer and step marks

   1. $\text{KOH}$ absorbs the carbon dioxide released by the germinating seeds.+1
   2. The oxygen used by the seeds is therefore not replaced by any gas, so the pressure in the flask falls and water rises in the bent delivery tube.+1

   Answer: $\text{KOH}$ absorbs the $\text{CO}_2$ released, so the oxygen used up is not replaced; pressure falls and water rises in the delivery tube.
5. Q5Long answer·4 marks
   Compare photosynthesis and respiration in green plants by answering the following: (a) Differentiate between the two processes on the basis of: (i) Raw materials required (ii) Nature of energy change (storage vs release) (b) Explain briefly how photosynthesis and respiration are considered complementary processes in nature.
   Show answer and step marks

   1. (a) (i) Raw materials: Photosynthesis uses carbon dioxide and water, whereas respiration uses glucose and oxygen.+1
   2. (a) (ii) Energy change: Photosynthesis is an anabolic process that traps light energy and stores it as chemical energy in glucose, whereas respiration is a catabolic process that breaks down glucose to release energy for cellular activities.+1
   3. (b) Complementary nature: The end products of photosynthesis (glucose and oxygen) are the raw materials required for respiration. Conversely, the end products of respiration (carbon dioxide and water) are used as raw materials for photosynthesis, thereby maintaining the balance of oxygen and carbon dioxide in the atmosphere.+2

   Answer: (a) (i) Photosynthesis uses carbon dioxide and water; respiration uses glucose and oxygen. (ii) Photosynthesis stores light energy as chemical energy in glucose; respiration releases that energy. (b) The products of photosynthesis (glucose, oxygen) are the raw materials of respiration, and the products of respiration (carbon dioxide, water) are the raw materials of photosynthesis, keeping atmospheric oxygen and carbon dioxide balanced.
6. Q6Long answer·4 marks
   Differentiate between photosynthesis and respiration on the following bases: (a) Raw materials used (b) Energy change (c) Organelles involved (d) End products
   Show answer and step marks

   1. (a) Raw materials: Photosynthesis uses carbon dioxide and water; Respiration uses glucose and oxygen.+1
   2. (b) Energy change: Photosynthesis traps and stores solar energy as chemical energy; Respiration breaks down glucose to release stored energy as ATP.+1
   3. (c) Organelles involved: Photosynthesis takes place in chloroplasts; Respiration takes place in the cytoplasm and mitochondria.+1
   4. (d) End products: Photosynthesis produces glucose and oxygen; Respiration produces carbon dioxide, water, and energy.+1

   Answer: (a) Photosynthesis: carbon dioxide and water; respiration: glucose and oxygen. (b) Photosynthesis stores solar energy as chemical energy; respiration releases it as ATP. (c) Photosynthesis: chloroplasts; respiration: cytoplasm and mitochondria. (d) Photosynthesis: glucose and oxygen; respiration: carbon dioxide, water and energy.

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