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. 2
- B. 4
- C. 1
- D. 6
Explanation: Glycolysis comprises of two phases in 1st half, Glucose is converted into two 3 carbon compounds known as glyceraldehyde phosphate using 2…
Correct answer: 2- A. 2-phosphoglycerate → PEP
- B. 3-phosphoglycerate → 2-phosphoglycerate
- C. 1,3 bisphosphoglycerate → 3-phosphoglycerate
- D. G3P → 1,3 bisphosphoglycerate
- E. None of these
Explanation: Water is released during conversion of 2-phosphoglycerate to phosphoenolpyruvate. So, A is correct option.
Correct answer: 2-phosphoglycerate → PEP- A. Fructose I-phosphate → Fructose 1,6-biphosphate
- B. Fructose 1 ,3 bisphosphoglyeerate → 3 phosphoglycerate
- C. Fructose I-phosphate → Fructose 6-phosphate
- D. Glucose 6-phosphate → Fructose 1-phosphate
Explanation: Removal of phosphate group from a molecule is called de-phosphorylation.
Correct answer: Fructose 1 ,3 bisphosphoglyeerate → 3 phosphoglycerate- A. 2 NADH, 2 FADH2, 2 ATP
- B. 1 NADH, 1 FADH2, 1 ATP
- C. 1 NADH, 3 FADH2, 2 ATP
- D. 6 NADH, 2 FADH2, 2 ATP
Explanation: When products of glycolysis pass through Krebs cycle it will produce 6 molecules of NADH. 2 molecules of FADH2 and 2 molecules of ATP.
Correct answer: 6 NADH, 2 FADH2, 2 ATP- A. Amino acid aspartate
- B. Fumarate dehydrogenase
- C. Succinate dehydrogenase
- D. FAD+ Oxidase
Explanation: Therefore, amino acid aspartate is required as a precursor for the synthesis of fumarate in the Krebs cycle.
Correct answer: Succinate dehydrogenase- A. NADH
- B. FADH2
- C. ATP
- D. ADP
Explanation: Before pyruvate enters the citric acid cycle, it is decarboxylated, oxidized, and combined with coenzyme A, forming acetyl CoA, carbon…
Correct answer: NADH- A. Decarboxylation
- B. Dehydration
- C. Dehydrogenation
- D. Both A and C
Explanation: When pyruvate molecule is converted into acetyl CoA, one carbon ofpyruvate is removed in the form of carbon dioxide (decarboxylation)…
Correct answer: Both A and C- A. Carboxylase
- B. Hydrogenase
- C. Dehydrogenase
- D. Catalase
Explanation: Biological oxidation involves the removal of hydrogen. a redox reaction catalyzed by the dehydrogenases, linked to a specific coenzyme.
Correct answer: Dehydrogenase- A. a-kerogluteric acid
- B. Glyceric acid
- C. Citirc acid
- D. Acetaldehyde
Explanation: Glycolysis results in pyruvate fonnation. It enters mitochondria where an enzyme pyruvatc decarboxylase removes carbon dioxide from it.
Correct answer: Acetaldehyde- A. Cytochrome a
- B. Cytochrome b
- C. Cytochrome a3
- D. Cytochrome a complex
Explanation: In electron- transport chain electrons moves through proteins named as electron carriers.
Correct answer: Cytochrome b- A. Cytochrome a
- B. Cytochrome b
- C. Oxygen
- D. Hydrogen
Explanation: The final electron acceptor in the respiratory chain is oxygen (O2). During oxidative phosphorylation, electrons are passed along a series…
Correct answer: Oxygen- A. Synthesize NADP+
- B. Synthesize ADP
- C. Create electron gradient
- D. Create proton gradient
Explanation: The explanation for this question will be added soon!
Correct answer: Create proton gradient- A. Light reactions
- B. Dark reactions
- C. Chemiosmosis
- D. Fermentation
Explanation: ATP formation through oxidative phosphorylation involves the transfer of electrons from NADH and FADH2 to a series of electron carriers…
Correct answer: Chemiosmosis- A. Glucose
- B. Dihydroxyacetone
- C. Glyceraldehyde 3-phosphate
- D. Fructose
Explanation: The aldose sugar that is an intermediate between respiration and photosynthesis is glyceraldehyde-3-phosphate (G3P).
Correct answer: Glyceraldehyde 3-phosphate- A. 18
- B. 16
- C. 9
- D. 20
Explanation: When an 18-carbon fatty acid is broken down by beta-oxidation, it is first converted into 9 molecules of acetyl-CoA, which can then enter…
Correct answer: 9- A. Liver
- B. Kidney
- C. Pancreas
- D. Gall bladder
Explanation: Deamination of amino acids takes place in the liver. The liver is a major site of amino acid metabolism, and it is responsible for…
Correct answer: Liver- A. Photolysis
- B. ATP synthesis
- C. Transport of electrons
- D. Dark reaction
Explanation: Photolysis, also known as photodissociation or photodecomposition, refers to the process in which a substance is broken down or decomposed…
Correct answer: Photolysis- A. Isocitrate → a-ketoglutarate
- B. Pyruvate → Acetyl CoA
- C. a-ketoglutarate → succinate
- D. Malate → oxaloacetate
Explanation: The explanation for this question will be added soon!
Correct answer: Malate → oxaloacetate- A. Malate
- B. Fumarate
- C. FAD
- D. Succinate
Explanation: Succinate is a dicarboxylic acid and a key intermediate in the citric acid cycle, also known as the Krebs cycle or tricarboxylic acid…
Correct answer: Succinate- A. Red light
- B. Blue light
- C. Green light
- D. Ultra-violet light
Explanation: When light having a wavelength ranging between 400-and 700 nm is absorbed by the plant, the rate of photosynthesis is the highest.
Correct answer: Red light