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.
Last updated
Read the Bioenergetics notesFree MDCAT chapter notes with key terms1,378 questions · page 56 of 69
- A. 2 & 3
- B. 3 & 4
- C. 4 & 5
- D. 5 & 6
Explanation: Fructose 1, 6 bisphosphate splits up into glyceroldehyde 3.phosphate and dihydroxyacetone phosphate during step no.4 of glycolysis which…
Correct answer: 4 & 5- A. Step - 4
- B. Step - 6
- C. Step - 5
- D. Step - 7
Explanation: In step no. 7 of glycolysis, two molecules of 1, 3 bisphosphoglycerate are dephosphorylated, two molecules of ADP are phosphorylated to…
Correct answer: Step - 71103. The oxidation - reduction substances which take part in respiratory chain are following EXCEPT:
- A. Coenzyme Q
- B. Molecular oxygen
- C. Cytochromes b, c, a and a3
- D. Cytochrome f
Explanation: Cytochrome f is a protein involved in photosynthesis and is not part of the respiratory chain.
Correct answer: Cytochrome f- A. NADH
- B. FADH
- C. Coenzyme Q
- D. Cytochrome C
Explanation: It is first step of respiratory electron transport chain in which NADH is oxidized by coenzyme Q.
Correct answer: NADH- A. NADH
- B. Cytochrome - C
- C. FADH
- D. Cytochrome - a
Explanation: As NADH stands at higher energy level and electron move from higher to lower energy level, thus NADH is oxidized and coenzymes Q is reduced.
Correct answer: NADH- A. NADH
- B. FADH
- C. Cytochrome - C
- D. Coenzyme - Q
Explanation: Cytochrome-b is reduced by electrons which are released by the oxidation of coenzyme Q.
Correct answer: Coenzyme - Q- A. NADH
- B. FADH
- C. Cytochrome - C
- D. Coenzyme - Q
Explanation: Cytochrome-a is reduced by cytochrome c which is oxidized and electrons are used to reduced cytochrome a
Correct answer: Cytochrome - C- A. NADH
- B. Cytochrome - b
- C. Cytochrome - c
- D. Cytochrome - a3
Explanation: When cytochrome a3 is oxidized and O2 is reduced to form water, electrons release some free energy to come to the lower energy state and…
Correct answer: Cytochrome - a3- A. Glycolysis
- B. Respiratory chain
- C. Kreb's cycle
- D. Photosynthetic electron transport chain
Explanation: This is summary equation of respiratory electron transport chain.
Correct answer: Respiratory chain- A. Oxidative phosphorylation
- B. Cyclic phosphorylation
- C. Photophosphorylation
- D. Non-cyclic phosphorylation
Explanation: The organelle (mitochondrion) clearly indicates it.
Correct answer: Oxidative phosphorylation- A. Citrate
- B. Oxaloacetate
- C. Succinate
- D. Adenosine triphosphate
Explanation: Citrate is a key molecule in cellular metabolism, playing a central role in both glycolysis and the citric acid cycle (also known as the…
Correct answer: Citrate- A. Electron debt
- B. Oxygen debt
- C. Hydrogen debt
- D. Carbon debt
Explanation: It have been taken from glossary of text book of biology book-I. It is definition of oxygen debt.
Correct answer: Oxygen debt- A. Ferredoxin
- B. ATP synthase
- C. Cytochrome complex
- D. Plastoquinone
Explanation: ATP synthase is an important enzyme that creates the energy storage molecules adenosine triphosphate (ATP).
Correct answer: ATP synthase- A. Glucose 6-PO4 to fructose 6-PO4
- B. Glyceraldehyde 3 - phosphate to 1, 3 - bisphosphoglycerate
- C. 1. 3 - bisphosphoglycerate to 3 - phosphoglycerate
- D. 2 - phosphoglycerate to phosphoenol pyruvate
Explanation: Oxidation is the loss of electrons by an atom or molecule. In glycolysis, there are two main reactions that involve…
Correct answer: Glyceraldehyde 3 - phosphate to 1, 3 - bisphosphoglycerate- A. Succinyl CoA to succinic acid.
- B. α - ketoglutarate to succinyl CoA
- C. Succinic acid to fumaric acid
- D. Fumaric acid to malic acid
Explanation: The FAD electron transport system operates during the conversion of succinate to fumarate in the Krebs cycle.The Krebs cycle, also known…
Correct answer: Succinic acid to fumaric acid- A. 12ATP and 12NADPH2
- B. 12ATP and 18NADPH
- C. 18ATP and 12NADPH2
- D. 9ATP and 6NADPH
Explanation: The synthesis of one mole of glucose from carbon dioxide and water in the Calvin cycle requires 18 ATP and 12 NADPH.
Correct answer: 18ATP and 12NADPH2- A. Outer membrane of mitochondrion
- B. Inner membrane of mitochondrion
- C. Matrix of mitochondrion
- D. Inner side of thylakoid membrane
Explanation: The molecular mechanism of oxidative phosphorylation takes place in conjunction with the respiratory chain in the mitochondrial inner…
Correct answer: Inner membrane of mitochondrion- A. Cyclic photophosphorylation
- B. Non - cyclic photophosphorylation
- C. Chemiosmosis
- D. Oxidative phosphorylation
Explanation: The process that uses membranes to couple redox reactions to ATP production is called chemiosmosis.Chemiosmosis is a process that occurs…
Correct answer: Chemiosmosis- A. 2
- B. 3
- C. 4
- D. 5
Explanation: Two electrons flow from a single molecule of H2O to reduce NADP+ in non-cyclic photophosphorylation.
Correct answer: 2- A. Cytochrome
- B. Plastoquinone
- C. Plastocyanin
- D. Ferredoxin
Explanation: Plastocyanin is a copper-containing protein that is found in the thylakoid membranes of chloroplasts.
Correct answer: Plastocyanin