Free Bioenergetics MCQs with Answers
1,378 Bioenergetics MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Cellular respiration explains how cells release energy from glucose through glycolysis, the link reaction, Krebs cycle and electron transport chain. It includes ATP production, substrate-level and oxidative phosphorylation, aerobic versus anaerobic respiration, and the roles of mitochondria, oxygen and fermentation in energy transfer.
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- A. ATP→ADP
- B. ADP→ATP
- C. NAD+→NADH
- D. NADH→NAD+
Explanation: During the preparatory phase of glycolysis, 2 molecules of ATP are invested to convert glucose to Glucose-6-phosphate and…
Correct answer: ATP→ADP- A. C6H12O6 → 2 C3H6O3
- B. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
- C. C6H12O6 → 2 C2H5OH + 2 CO2
- D. C6H12O6 → 6 CO2 + 6 H2O
Explanation: The correct equation for the conversion of glucose into lactic acid during anaerobic respiration is C6H12O6 → 2 C3H6O3.
Correct answer: C6H12O6 → 2 C3H6O3- A. Breakdown of pyruvic acid into ethanol
- B. Formation of pyruvic acid from glucose
- C. Breakdown of pyruvic acid into lactic acid
- D. Release of carbon dioxide gas from pyruvic acid
Explanation: The correct answer is the formation of pyruvic acid from glucose. This step is known as glycolysis, which is the initial stage of both…
Correct answer: Formation of pyruvic acid from glucose- A. Glycolysis
- B. Krebs cycle
- C. Pyruvate oxidation
- D. Electron transport chain
Explanation: The correct answer is the Krebs cycle.During cellular respiration, NADH and FADH2 are primarily produced in the Krebs cycle.
Correct answer: Krebs cycle- A. A.
- B. B.
- C. C.
- D. D.
Explanation: The correct answer is the formation of pyruvic acid from glucose. This step is known as glycolysis, which is the initial stage of both…
Correct answer: B.1186. β-oxidation occurs in
- A. Nucleus
- B. Cytoplasm
- C. Mitochondria
- D. Chloroplast
Explanation: β-Oxidation is a process that occurs in the mitochondria.It involves the breakdown of fatty acids into acetyl-CoA, which enters the citric…
Correct answer: Mitochondria- A. Isocitric acid → Oxalosuccinic acid → α-Ketoglutaric acid
- B. Oxalosuccinic acid → Isocitric acid → α-Ketoglutaric acid
- C. α-Ketoglutaric acid → Isocitric acid → Oxalosuccinic acid
- D. Isocitric acid → α-Ketoglutaric acid → Succinic acid
Explanation: The correct sequence in the Krebs cycle is: Isocitric acid → α-Ketoglutaric acid → Succinic acid.
Correct answer: Isocitric acid → α-Ketoglutaric acid → Succinic acid- A. Light absorption
- B. Consumption of carbon dioxide
- C. Light emission
- D. Both A and B
Explanation: An action spectrum typically illustrates the relative effectiveness of different wavelengths of light in driving a specific biological…
Correct answer: Consumption of carbon dioxide- A. Presence of enzyme in high concentration
- B. Absence of Rubisco
- C. PEP carboxylase being strictly carboxylase
- D. High yield of enzyme
Explanation: PEP carboxylase is an enzyme that plays a crucial role in the C4 photosynthetic pathway.
Correct answer: PEP carboxylase being strictly carboxylase- A. Glucose
- B. Pyruvate
- C. Acetyl CoA
- D. CO2
Explanation: Glycolysis converts glucose to 2 pyruvate molecules, with net gain of 2 ATP and 2 NADH.
Correct answer: Pyruvate- A. Alcoholic fermentation
- B. Lactic acid fermentation
- C. Aerobic respiration
- D. None of these
Explanation: Aerobic respiration is the process where glucose is completely broken down in the presence of oxygen.
Correct answer: Aerobic respiration1192. Air contains _% of CO₂.
- A. 0.3%
- B. 0.03-0.04
- C. 3%
- D. 30%
Explanation: The concentration of carbon dioxide in air is approximately 0.03-0.04%.
Correct answer: 0.03-0.04- A. Leaves respire utilizing O2 and releasing CO2
- B. Photosynthesis and respiration occur at the same rate, resulting in no net exchange of gases between the atmosphere and plants
- C. The rate of photosynthesis increases, resulting in a net release of oxygen and uptake of CO2
- D. The rate of respiration exceeds the rate of photosynthesis, resulting in a net release of carbon dioxide
Explanation: The compensation point is a specific condition in plant physiology where the rates of photosynthesis and respiration are equal.
Correct answer: Photosynthesis and respiration occur at the same rate, resulting in no net exchange of gases between the atmosphere and plants- A. Glucose-6-phosphate
- B. Fructose-6-phosphate
- C. Pyruvate
- D. 3-Phosphoglycerate
- E. Phosphoglyceraldehyde
Explanation: The end product of glycolysis is pyruvate. During glycolysis, one molecule of glucose is broken down into two molecules of pyruvate…
Correct answer: Pyruvate- A. T. W. Engelmann
- B. Darwin
- C. Robert Hooke
- D. Schwan
Explanation: The first action spectrum was obtained by German biologist T.W.England in 1833. He worked on Spirogyra.
Correct answer: T. W. Engelmann- A. CO₂
- B. ATP
- C. Water
- D. Oxygen
Explanation: In cellular respiration, the final acceptor of electrons in the respiratory chain is oxygen (O₂).
Correct answer: Oxygen- A. ATP synthesis
- B. Reduction of NADP
- C. Cyclic phosphorylation
- D. Oxidation of the reaction center of photosystem I
Explanation: Non-cyclic photophosphorylation is the light-dependent part of photosynthesis in higher plants, in which an electron donor is required…
Correct answer: Reduction of NADP- A. Stroma
- B. Grana
- C. Thylakoid
- D. lntergrana
Explanation: Chlorophylls are found embedded in the thylakoid membranes of chloroplasts.
Correct answer: Thylakoid- A. Leaf
- B. Stem
- C. Roots
- D. Branches
Explanation: The correct answer is 'Leaf'. In most plants, leaves are the primary sites for photosynthesis.
Correct answer: Leaf- A. Alcoholic fermentation
- B. Lactic acid fermentation
- C. Respiration
- D. Both A and B
Explanation: Pyruvate is produced in both of the processes as glycolysis continues to occur even in the absence of oxygen.
Correct answer: Both A and B