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. Energy is consumed
- B. Light is consumed
- C. Energy is released
- D. Light is produced
Explanation: During aerobic respiration glucose is broken down in the presence of oxygen into carbon dioxide and water and energy is produced.
Correct answer: Energy is released1082. Cristae are part of:
- A. Chloroplast
- B. Endoplasmic reticulum
- C. Mitochondrion
- D. Golgi apparatus
Explanation: Each mitochondrion is constructed of an outer enclosing membrane and an inner membrane with elaborate folds or cristae that extend into…
Correct answer: Mitochondrion- A. Organelles
- B. Coenzymes
- C. Enzymes
- D. Enzyme and coenzymes
Explanation: Aerobic respiration being a long pathway involves many enzymes and coenzymes.
Correct answer: Enzyme and coenzymes- A. NADH
- B. FADH
- C. ATP
- D. Glucose
Explanation: That is why it is called energy currency of the cell.
Correct answer: ATP- A. Phosphorus atom
- B. Entire phosphate group
- C. Phosphorus element
- D. Phosphorus acid
Explanation: Conventionally, "P" stands for the entire phosphate group. The second and third phosphate represent the so called "high energy" bonds.
Correct answer: Entire phosphate group- A. First
- B. Third
- C. Second
- D. Second and third
Explanation: The second and third phosphate represent the so called "high energy" bonds.
Correct answer: Second and third- A. High energy 'P' bond
- B. High energy bonds of organic food
- C. High energy bonds of glucose
- D. High energy bonds of lipids
Explanation: The energy of organic food is extracted from its bonds through aerobic respiration and is called ATP (in high energy 'p' bond).
Correct answer: High energy 'P' bond- A. Internal respiration
- B. Biological oxidation
- C. Organismic respiration
- D. Internal respiration and biological oxidation
Explanation: Based on the explanations provided, the correct answer to the question is option D) Internal respiration and biological oxidation.
Correct answer: Internal respiration and biological oxidation- A. Presence of oxygen
- B. Absence of oxygen
- C. Presence or absence of oxygen
- D. High Conc. of oxygen
Explanation: Based on the explanations provided, the correct answer to the question is option C) Presence or absence of oxygen.
Correct answer: Presence or absence of oxygen- A. Glucose
- B. ATP
- C. Enzymes and Coenzymes
- D. FAD
Explanation: Based on the explanations provided, the correct answer to the question is option D) FAD.
Correct answer: FAD- A. Glucose 6-phosphate
- B. Fructose 1, 6 Bisphosphate
- C. Fructose 6-phosphate
- D. Glucose
Explanation: Aldohexose (glucose 6 phosphate) is transformed into ketohexose (fructose 6 phosphate).
Correct answer: Fructose 6-phosphate- A. G3P
- B. 3PGAL
- C. Dihydroxyacetone phosphate
- D. G.3.P/PGAL and Dihydroxyacetone phosphate
Explanation: As fructose 1, 6 bisphosphate is cleaved to yield two trioses i.e. Glyceraldehyde 3 phosphate and dihydroxyacetone phosphate.
Correct answer: G.3.P/PGAL and Dihydroxyacetone phosphate- A. 3PG → 2PG
- B. 2PG → PEP
- C. PEP → Pyruvate
- D. 1,3 BPG → 3PG
Explanation: Dehydration occurs during the formation of phosphenol pyruvate from 2 phosphoglyceraldehyde.
Correct answer: 2PG → PEP- A. G3P
- B. 3PGAL
- C. 3-PG
- D. Pyruvate
Explanation: Pyruvic acid (pyruvate) is the end product of glycolysis and does not enter the Krebs cycle directly.
Correct answer: Pyruvate- A. Pyruvic acid
- B. Acetyl CO-A
- C. Acetic acid
- D. Citric acid
Explanation: Acetic acid on entering the mitochondrion unites with Coenzyme A to form acetyl Co-A.
Correct answer: Acetic acid- A. Formation of acetyl-Co-A
- B. Oxidation of acetate
- C. Reduction of NAD
- D. Decarboxylation of pyruvate
Explanation: Oxidation of pyruvate takes places not that of acetate.
Correct answer: Oxidation of acetate- A. Oxidation process is completed
- B. Decarboxylation process is completed
- C. Reduction process is completed
- D. Energy consuming process is completed
Explanation: Oxidative breakdown of organic food is completed.
Correct answer: Oxidation process is completed- A. Formation of citrate
- B. Condensation of oxaloacetate and acetyl Co-A
- C. Hydration and decondensation of Co-A
- D. Decarboxylation and condensation of Co-A
Explanation: Other three changes given in A), B) and C) occur in first step of Krebs cycle except decarboxylation and condensation of Co-A.
Correct answer: Decarboxylation and condensation of Co-A- A. Succinate to fumarate
- B. Malate to oxaloacetate
- C. Fumarate to malate
- D. α-ketogluterate to succinate
Explanation: The succinate is oxidized to get fumarate in presence of succinic acid dehydrogenase enzyme.
Correct answer: Succinate to fumarate- A. A hydrogen atom
- B. A CO2 atom
- C. Two hydrogen atoms
- D. A water molecule
Explanation: Succinate is converted into fumarate and two hydrogen atoms are removed. The process is catalyzed by succinic acid dehydrogenase.
Correct answer: Two hydrogen atoms