MCQ Biology Chapter 12: RESPIRATION IN PLANTS, HS 1st year

 

MCQs: Respiration in Plants

1. What is the main site of aerobic respiration in eukaryotic cells?
   a) Chloroplast
   b) Cytoplasm
   c) Mitochondria
   d) Ribosome
   Answer: c) Mitochondria

2. Which of the following acts as the energy currency of the cell?
   a) NADH
   b) FADH2
   c) Glucose
   d) ATP
   Answer: d) ATP

3. The process of glycolysis occurs in the:
   a) Nucleus
   b) Mitochondria
   c) Cytoplasm
   d) Chloroplast
   Answer: c) Cytoplasm

4. During anaerobic respiration in yeast, glucose is converted into:
   a) Lactic acid
   b) Ethanol and CO₂
   c) Water and CO₂
   d) Pyruvate only
   Answer: b) Ethanol and CO₂

5. What is the respiratory quotient (RQ) when carbohydrates are used as a substrate?
   a) 0.7
   b) 0.9
   c) 1.0
   d) 1.2
   Answer: c) 1.0

6. Which enzyme is involved in the conversion of glucose to glucose-6-phosphate?
   a) Hexokinase
   b) Pyruvate dehydrogenase
   c) Alcohol dehydrogenase
   d) Citrate synthase
   Answer: a) Hexokinase

7. In the Krebs’ cycle, acetyl CoA combines with which compound to form citric acid?
   a) Pyruvate
   b) Succinic acid
   c) Oxaloacetic acid
   d) α-ketoglutaric acid
   Answer: c) Oxaloacetic acid

8. What is the net gain of ATP molecules during aerobic respiration of one glucose molecule?
   a) 2
   b) 38
   c) 30
   d) 12
   Answer: b) 38

9. Which of the following processes does not require oxygen?
   a) Krebs’ cycle
   b) Glycolysis
   c) Electron Transport Chain
   d) Oxidative phosphorylation
   Answer: b) Glycolysis

10. The term "amphibolic pathway" in respiration refers to:
    a) Energy production only
    b) Involvement in both breakdown and synthesis of molecules
    c) Release of carbon dioxide only
    d) Anaerobic processes
    Answer: b) Involvement in both breakdown and synthesis of molecules

12. Which molecule is the final electron acceptor in the Electron Transport System (ETS)?
    a) Carbon dioxide
    b) Oxygen
    c) NADH
    d) ATP
    Answer: b) Oxygen

13. Which of the following processes produces the highest number of ATP molecules?
    a) Glycolysis
    b) Fermentation
    c) Krebs’ Cycle
    d) Electron Transport System
    Answer: d) Electron Transport System

14. During fermentation, which molecule acts as the reducing agent?
    a) NADH
    b) FADH2
    c) Oxygen
    d) ATP
    Answer: a) NADH

15. What is the primary respiratory substrate in most organisms?
    a) Fats
    b) Proteins
    c) Carbohydrates
    d) Nucleic acids
    Answer: c) Carbohydrates

16. In aerobic respiration, the pyruvate formed during glycolysis is converted into:
    a) Lactic acid
    b) Acetyl CoA
    c) Ethanol
    d) Glyceraldehyde-3-phosphate
    Answer: b) Acetyl CoA

17. Which of the following statements about fermentation is correct?
    a) It requires oxygen.
    b) It produces large amounts of ATP.
    c) It involves incomplete oxidation of glucose.
    d) It occurs in mitochondria.
    Answer: c) It involves incomplete oxidation of glucose.

18. In the Electron Transport System (ETS), the energy released during electron transfer is used to:
    a) Generate heat
    b) Pump protons across the inner mitochondrial membrane
    c) Produce glucose
    d) Convert pyruvate to acetyl CoA
    Answer: b) Pump protons across the inner mitochondrial membrane

19. What is the role of the F₁ component of ATP synthase?
    a) Proton transport
    b) Synthesis of ATP
    c) Reduction of NAD+
    d) Conversion of pyruvate to acetyl CoA
    Answer: b) Synthesis of ATP

20. In which part of the cell does the Krebs’ cycle occur?
    a) Cytoplasm
    b) Outer mitochondrial membrane
    c) Mitochondrial matrix
    d) Intermembrane space
    Answer: c) Mitochondrial matrix

21. Which coenzymes are involved in oxidative phosphorylation during respiration?
    a) NAD+ and FAD
    b) ATP and ADP
    c) NADP+ and CoA
    d) GTP and NADPH
    Answer: a) NAD+ and FAD