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. 700 nm
- B. 730 nm
- C. 680 nm
- D. 660 nm
Explanation: Photosystem I contains a specific form of chlorophyll a known as P700, which is named after its optimal absorption of light at 700 nm.
Correct answer: 700 nm- A. Primary electron acceptor
- B. Chlorophyll b
- C. Accessory pigments
- D. Carotenoids
Explanation: The correct answer is the primary electron acceptor. In the light-dependent reactions of photosynthesis, the primary electron acceptor is…
Correct answer: Primary electron acceptor- A. Non-cyclic electron flow
- B. Z-scheme
- C. Cyclic electron flow
- D. Non-cyclic electron flow or Z - scheme
Explanation: The correct answer is non-cyclic electron flow. This pathway is the main route for electron transport during the light-dependent reactions…
Correct answer: Non-cyclic electron flow or Z - scheme- A. Non-cyclic electron flow
- B. Z-scheme
- C. Cyclic electron flow
- D. Non-cyclic electron flow or Z-scheme
Explanation: The correct answer is 'cyclic electron flow' because it involves only photosystem I and results exclusively in the production of ATP…
Correct answer: Cyclic electron flow- A. Z - scheme
- B. Light reaction
- C. Non-cyclic phosphorylation
- D. Synthesis of ATP and NADPH2
Explanation: In photosynthesis, non-cyclic phosphorylation refers to the process where electrons flow from water through Photosystem II and Photosystem…
Correct answer: Non-cyclic phosphorylation- A. Cyclic phosphorylation
- B. Non-cyclic photophosphorylation
- C. Oxidative phosphorylation
- D. Z-scheme
Explanation: The correct answer is cyclic photophosphorylation. In this process, electrons are cycled back to Photosystem I after passing through an…
Correct answer: Cyclic phosphorylation787. The splitting up of a water molecule into two hydrogen ions and an oxygen atom by light is called:
- A. Electrolysis of water
- B. Ionization of water
- C. Photolysis of water
- D. Autolysis
Explanation: The correct answer is photolysis of water. In the light-dependent reactions of photosynthesis, light energy is used to split water…
Correct answer: Photolysis of water- A. PS → Cytochrome complex → PQ
- B. PQ → PC → Cytochrome complex
- C. Cytochrome complex → PQ → PC
- D. PQ → Cytochrome complex → PC
Explanation: The correct sequence in the photosynthetic electron transport chain, particularly in non-cyclic photophosphorylation, starts with the…
Correct answer: PQ → Cytochrome complex → PC789. Pick up the one not involved in the cyclic electron flow of the light reaction of photosynthesis:
- A. PQ
- B. PC
- C. Cytochrome complex
- D. Fd
Explanation: In cyclic photophosphorylation, electrons excited by light in Photosystem I are cycled back through a specific chain of carriers to…
Correct answer: PC- A. ATP
- B. Water
- C. Oxygen
- D. NADPH
Explanation: During the light-dependent reactions of photosynthesis, electrons are excited by light energy and pass through a series of proteins in the…
Correct answer: ATP- A. ATPs generated by light reactions
- B. NADPH generated by light reactions
- C. FADH2 generated by light reactions
- D. Oxygen generated by light reactions
Explanation: The Calvin cycle, also known as the light-independent reactions or dark reactions of photosynthesis, relies on ATP for the energy to drive…
Correct answer: ATPs generated by light reactions- A. Non-cyclic photophosphorylation
- B. Cyclic photophosphorylation
- C. Z-scheme
- D. Fermentation
Explanation: Cyclic electron flow is the correct answer, as it exclusively utilizes photosystem I, bypassing photosystem II.
Correct answer: Cyclic photophosphorylation- A. Photosystem I
- B. Photosystem II
- C. ETC
- D. Calvin cycle
Explanation: ATP in photophosphorylation is generated through the electron transport chain, making it the correct option.
Correct answer: ETC- A. Photosynthesis
- B. Respiration
- C. Both A and B
- D. Fermentation
Explanation: Chemiosmosis is the process that produces ATP by using a proton gradient across a membrane, and it takes place in both photosynthesis and…
Correct answer: Both A and B- A. Oxford University
- B. University of California
- C. Cambridge University
- D. Tubingen University
Explanation: The correct answer is the University of California, where Melvin Calvin and his colleagues elucidated the path of carbon in the dark…
Correct answer: University of California- A. Cyclic phosphorylation
- B. Calvin cycle
- C. Non-cyclic phosphorylation
- D. Z-scheme
Explanation: The correct answer is the Calvin cycle. This cycle is the set of light-independent reactions where carbon dioxide is fixed and reduced to…
Correct answer: Calvin cycle- A. Reduction
- B. Regeneration
- C. Fixation of CO2
- D. Photolysis
Explanation: The first phase of the Calvin cycle is the carbon fixation phase, which makes option A correct.
Correct answer: Fixation of CO2- A. Ribulose bisphosphate
- B. Fructose-1,6-bisphosphate
- C. Glucose-6-phosphate
- D. Glyceraldehyde-3-phosphate
Explanation: The Calvin cycle begins when carbon dioxide reacts with ribulose-1,5-bisphosphate, a five-carbon compound that serves as the starting…
Correct answer: Ribulose bisphosphate- A. 3-phosphoglycerate is phosphorylated to form 1,3-bisphosphoglycerate using ATP
- B. 1,3-bisphosphoglycerate is reduced to glyceraldehyde-3-phosphate using NADPH
- C. Ribulose-1,5-bisphosphate reacts with carbon dioxide to form 3-phosphoglycerate
- D. Glyceraldehyde-3-phosphate combines to form glucose directly
Explanation: In the first step of the reduction phase of the Calvin cycle, 3-phosphoglycerate is phosphorylated to form 1,3-bisphosphoglycerate using…
Correct answer: 3-phosphoglycerate is phosphorylated to form 1,3-bisphosphoglycerate using ATP- A. Fixation phase of Calvin cycle
- B. Regeneration phase of Calvin cycle
- C. Reduction phase of Calvin cycle
- D. Condensation phase of Calvin cycle
Explanation: The Calvin cycle consists of three main phases: fixation, reduction, and regeneration.
Correct answer: Reduction phase of Calvin cycle