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. Pyruvate enters and ATP leaves
- B. Glucose enters and carbon dioxide leaves
- C. Oxygen enters and water leaves
- D. NADH enters and FAD leaves
Explanation: During aerobic respiration, pyruvate produced from glycolysis enters the mitochondria, where it is converted into acetyl-CoA, which enters…
Correct answer: Pyruvate enters and ATP leaves- A. CO2 + H2O + Light → CH2O + O2
- B. C6H12O6 + 6H2O → 6CO2 + 6H2O
- C. 6CO2 + 6H2O → C6H12O6 + 6O2
- D. 6CO2 + 12H2O + Light → C6H12O6 + 6O2 + 6H2O
Explanation: Option D is correct because it describes the complete photosynthetic process where carbon dioxide (6CO2) and water (12H2O), in the…
Correct answer: 6CO2 + 12H2O + Light → C6H12O6 + 6O2 + 6H2O- A. C6HI2O6 containing18O
- B. H2O containing 18O
- C. CO6 containing 18O
- D. Oxygen in the form of ozone
Explanation: If a photosynthesizing plant releases oxygen containing more than the normal amount of 18O, it is concluded that the plant has been…
Correct answer: H2O containing 18O- A. Plasma membrane
- B. Thylakoids
- C. Cytoplasm
- D. Stroma
Explanation: The energy-capturing reactions of photosynthesis, commonly referred to as the light-dependent reactions, occur in the thylakoids of…
Correct answer: Thylakoids- A. Photosystem I
- B. Photosystem II
- C. ATP
- D. NADP+
Explanation: NADP+ acts as the final electron acceptor during non-cyclic electron flow, while electrons are moved back from ferredoxin to the…
Correct answer: NADP+- A. Dark reaction
- B. Non-cyclic photophosphorylation
- C. Photorespiration
- D. Cyclic photophosphorylation
Explanation: NADP is converted into NADPH₂ during non-cyclic photophosphorylation, which occurs in the light reactions of photosynthesis.
Correct answer: Non-cyclic photophosphorylation- A. Ribulose bisphosphate
- B. Glycolate
- C. Phosphoenolpyruvate
- D. Triosephosphate
Explanation: In C3 plants, the Calvin cycle is the series of reactions that occur in the light-independent phase of photosynthesis.
Correct answer: Ribulose bisphosphate- A. Electron transfer
- B. Release of O2
- C. Photolysis of H2O
- D. Release of H2
Explanation: The light-dependent reactions of photosynthesis, also known as the light reactions, occur in the thylakoid membranes of chloroplasts.
Correct answer: Release of H2- A. NADP
- B. FADH2
- C. H2O
- D. ATP
Explanation: In the light-dependent reactions of photosynthesis, water (H2O) is split in a process known as photolysis.
Correct answer: H2O470. Cu is present in:
- A. Plastocyannin
- B. Cytochrome b6f
- C. Ferredoxin
- D. Chlorophyll
Explanation: Copper is present in plastocyanin, a protein that transfers electrons from the cytochrome b6f complex to Photosystem I during the light…
Correct answer: Plastocyannin- A. They reduce NADP
- B. They are transferred to pyruvic acid
- C. They are eliminated in the form of methane
- D. They reduce NAD+
Explanation: During glycolysis, specifically in the step where glyceraldehyde 3-phosphate is converted to 1,3-bisphosphoglycerate, NAD+ serves as an…
Correct answer: They reduce NAD+- A. FAD
- B. FADH
- C. FADH2
- D. NADH2
Explanation: In the citric acid cycle, succinate undergoes oxidation to form fumarate.
Correct answer: FADH2- A. Calvin cycle
- B. Krebs cycle
- C. Dark reaction
- D. Light reaction
Explanation: Fatty acids are broken down into acetyl-CoA molecules through a process called beta-oxidation.
Correct answer: Krebs cycle- A. Pyruvate
- B. CO2 and H2O
- C. CO2
- D. Lactic acid
Explanation: The correct answer is CO2 and H2O. During the citric acid cycle, acetyl-CoA is oxidized, resulting in the release of carbon dioxide (CO2).
Correct answer: CO2 and H2O- A. Calvin cycle
- B. Light reaction in photosynthesis
- C. Krebs cycle
- D. Glycolysis
Explanation: The light-dependent reactions of photosynthesis, also known as the light reactions, occur in the thylakoid membranes of chloroplasts and…
Correct answer: Light reaction in photosynthesis- A. C₅₅H₇₂O₅N₄Mg
- B. C₅₅H₇₀O₆N₄Mg
- C. C₅₅H₇₄O₅N₄Mg
- D. C₅₅H₇₀O₄N₄Mg
Explanation: Among the given options, option B (C₅₅H₇₀O₆N₄Mg) correctly represents the molecular formula of chlorophyll b, the pigment responsible for…
Correct answer: C₅₅H₇₀O₆N₄Mg- A. Inner membrane
- B. Grana
- C. Stroma
- D. Thylakoid
Explanation: The correct answer is the stroma of the chloroplast. This is where the Calvin Cycle, or dark reactions, occur.
Correct answer: Stroma- A. 4
- B. 6
- C. 5
- D. 7
Explanation: Rubisco takes carbon dioxide and attaches it to ribulose bisphosphate, a short sugar chain with five carbon atoms.
Correct answer: 5- A. Bioenergetics
- B. Photosynthesis
- C. Aerobic respiration
- D. Anerobic respiration
Explanation: Photosynthesis is the process in which light energy is absorbed by chlorophyll and other pigments to convert inorganic compounds such as…
Correct answer: Photosynthesis- A. Bacteriochlorophylls
- B. Redox process
- C. Photosystems
- D. Compensation point
Explanation: The condition in which the carbon dioxide released during respiration equals the amount of carbon dioxide utilized in photosynthesis is…
Correct answer: Compensation point