Respiration in plants MCQ with Answer and Explanation

31. Which of the following is a product of aerobic respiration but not of anaerobic respiration?

a) Oxygen
b) Carbon dioxide
c) ATP
d) Water

Answer: d) Water

Explanation: Water is produced during aerobic respiration when oxygen acts as the final electron acceptor in the electron transport chain.

32. The energy released during respiration is primarily stored in which molecule?

a) Glucose
b) NADH
c) ATP
d) FADH₂

Answer: c) ATP

Explanation: ATP stores and transports energy for cellular processes.

33. In which part of the plant does aerobic respiration take place?

a) In the chloroplasts
b) In the mitochondria
c) In the cytoplasm
d) In the vacuoles

Answer: b) In the mitochondria

Explanation: Aerobic respiration occurs in the mitochondria, where glucose is fully oxidized to produce ATP.

34. Which is a key difference between anaerobic and aerobic respiration?

a) Anaerobic respiration produces more ATP
b) Aerobic respiration does not require oxygen
c) Anaerobic respiration produces carbon dioxide and ethanol or lactic acid
d) Aerobic respiration occurs in the cytoplasm

Answer: c) Anaerobic respiration produces carbon dioxide and ethanol or lactic acid

Explanation: Anaerobic respiration produces different byproducts, such as ethanol or lactic acid, while aerobic respiration produces carbon dioxide and water.

35. Which of the following steps of cellular respiration takes place in the cytoplasm?

a) Krebs cycle
b) Glycolysis
c) Electron transport chain
d) Both b and c

Answer: b) Glycolysis

Explanation: Glycolysis takes place in the cytoplasm, while the Krebs cycle and electron transport chain occur in the mitochondria.

36. The number of ATP molecules produced during glycolysis is:

a) 1
b) 2
c) 4
d) 36

Answer: b) 2

Explanation: Glycolysis produces a net gain of 2 ATP molecules per glucose molecule.

37. Which of the following is produced in the Krebs cycle?

a) Oxygen
b) Glucose
c) Carbon dioxide
d) Water

Answer: c) Carbon dioxide

Explanation: Carbon dioxide is produced during the Krebs cycle as a byproduct of the breakdown of acetyl-CoA.

38. Which of the following occurs during the process of fermentation in plants?

a) Glucose is converted into pyruvate
b) Oxygen is used to break down glucose
c) ATP is produced in the absence of oxygen
d) Glucose is converted into ATP and oxygen

Answer: c) ATP is produced in the absence of oxygen

Explanation: Fermentation allows ATP production when oxygen is unavailable, producing ethanol and carbon dioxide as byproducts.

39. How many ATP molecules are generated by the complete oxidation of one molecule of glucose?

a) 2
b) 38
c) 32
d) 36

Answer: b) 38

Explanation: Under ideal conditions, the complete oxidation of glucose in aerobic respiration yields approximately 38 ATP molecules.

40. Which of the following is true for both aerobic and anaerobic respiration?

a) Oxygen is required
b) ATP is produced
c) Glucose is synthesized
d) Water is produced

Answer: b) ATP is produced

Explanation: Both aerobic and anaerobic respiration produce ATP, but the amounts and byproducts differ.