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. Fixation
- B. Regeneration
- C. Reduction
- D. Photolysis
Explanation: The Calvin cycle has three main phases: carbon fixation, reduction, and regeneration.
Correct answer: Reduction- A. 3, 6, 9
- B. 12, 24, 36
- C. 6, 12, 18
- D. 24, 48, 72
Explanation: The Calvin cycle is a series of biochemical reactions that occur in the stroma of chloroplasts during photosynthesis.
Correct answer: 3, 6, 9- A. 3, 6, 9
- B. 6, 12, 18
- C. 12, 24, 36
- D. 24, 48, 72
Explanation: The synthesis of one glucose molecule via the Calvin cycle requires 6 CO₂, 12 NADPH₂, and 18 ATP molecules.
Correct answer: 12, 24, 36- A. 6, 12, 18
- B. 1, 2, 3
- C. 3, 6, 9
- D. 12, 24, 36
Explanation: The correct stoichiometric ratio of CO₂, NADPH, and ATP molecules required to synthesize one glucose molecule via the Calvin Cycle is…
Correct answer: 6, 12, 18- A. 1, 2, 3
- B. 3, 6, 9
- C. 6, 12, 18
- D. 12, 24, 36
Explanation: The Calvin cycle, also known as the light-independent reactions of photosynthesis, uses 3 molecules of CO₂, 6 molecules of NADPH, and 9…
Correct answer: 3, 6, 9- A. 1, 2, 3
- B. 3, 6, 9
- C. 6, 12, 18
- D. 12, 24, 36
Explanation: To synthesize one molecule of glucose through the Calvin cycle, 6 molecules of CO₂, 12 molecules of NADPH₂, and 18 molecules of ATP are…
Correct answer: 6, 12, 18- A. Light reactions of photosynthesis
- B. Photosynthesis
- C. Dark reactions of photosynthesis
- D. Respiration
Explanation: The process described in the equation involves the fixation of carbon dioxide and its conversion into a three-carbon sugar using ATP and…
Correct answer: Dark reactions of photosynthesis- A. Oxidation of pyruvate
- B. Citric acid cycle
- C. Glycolysis
- D. Oxidative phosphorylation
Explanation: Glycolysis is the first stage of cellular respiration that takes place in the cytoplasm.
Correct answer: Glycolysis809. Pyruvate, the end product of glycolysis, follows different catabolic pathways depending on the:
- A. Organism
- B. Metabolic conditions
- C. Size of organism
- D. Organism and metabolic conditions
Explanation: Pyruvate, the end product of glycolysis, can undergo various metabolic pathways depending on the organism and its metabolic conditions.
Correct answer: Organism and metabolic conditions- A. Alcoholic fermentation
- B. Respiratory electron transport chain
- C. Lactic acid fermentation
- D. Both A and C
Explanation: In the absence of oxygen, cells can undergo anaerobic respiration, which includes processes like alcoholic fermentation and lactic acid…
Correct answer: Both A and C- A. Fermentation
- B. Oxidative phosphorylation
- C. Respiratory chain
- D. Krebs cycle
Explanation: Fermentation is the correct answer because it is an anaerobic process, meaning it occurs without oxygen.
Correct answer: Fermentation- A. Aerobic respiration
- B. Cellular respiration
- C. Internal respiration
- D. External respiration
Explanation: Aerobic respiration is the correct answer because it is the cellular process where glucose is completely oxidized in the presence of…
Correct answer: Aerobic respiration- A. Lactic acid
- B. CO2 and water
- C. Ethanol and CO₂
- D. Pyruvate
Explanation: During aerobic respiration, glucose is completely oxidized in the presence of oxygen to produce carbon dioxide, water, and energy in the…
Correct answer: CO2 and water- A. Stored as ATP
- B. Released as heat
- C. Stored as glycogen
- D. Stored as fat
Explanation: During aerobic respiration, glucose is completely oxidized to carbon dioxide and water, and the energy released in this process is…
Correct answer: Stored as ATP- A. Alcoholic fermentation
- B. Aerobic respiration
- C. Anaerobic respiration
- D. Lactic acid fermentation
Explanation: The correct answer is lactic acid fermentation. During intense physical activities like sprinting, the oxygen supply to muscle cells is…
Correct answer: Lactic acid fermentation- A. ATP
- B. NADH
- C. Glucose
- D. FADH₂
Explanation: ATP is the primary energy carrier in cells. It stores energy in its high-energy phosphate bonds and releases it to power essential…
Correct answer: ATP- A. NADH
- B. FADH₂
- C. ATP
- D. Glucose
Explanation: ATP is considered the energy currency of the cell because it directly provides energy for most cellular processes.
Correct answer: ATP- A. Continuous supply of free energy
- B. Continual supply of free energy
- C. Continuously increasing supply of free energy
- D. Continuously decreasing supply of free energy
Explanation: The correct answer is Option B: continual supply of free energy. Living organisms require a steady and ongoing influx of energy to support…
Correct answer: Continual supply of free energy- A. Oxidation process
- B. Redox process
- C. Reduction process
- D. Decarboxylation process
Explanation: The correct answer is Option A) Oxidation process. Cellular respiration is fundamentally an oxidation process, where organic molecules are…
Correct answer: Oxidation process- A. Internal respiration
- B. Biological oxidation
- C. Organismic respiration
- D. Both A and B
Explanation: Cellular respiration is best described as biological oxidation. This process involves the breakdown of organic compounds, such as glucose…
Correct answer: Biological oxidation