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. 24
- C. 6
- D. 28
Explanation: 1 ATP is received when one Krebs cycle turns, so in case so glucose, the Krebs cycle will turn for two times, we will get 2 ATP from the…
Correct answer: 2- A. ATP in one large oxidation reaction
- B. Sugars
- C. Nucleic acids
- D. ATP in small stepwise units
Explanation: The overall purpose of these metabolic pathways is to gradually extract energy from glucose and use it to produce ATP through a series of…
Correct answer: ATP in small stepwise units- A. Alpha-ketoglutarate
- B. Malate
- C. Malonate
- D. Oxaloacetate
Explanation: Malonate is a competitive inhibitor of succinic dehydrogenase. It mimics the structure of succinate, the natural substrate, allowing it to…
Correct answer: Malonate- A. H2O + CO2
- B. Methyl alcohol + CO2
- C. Methyl alcohol + O2
- D. Ethyl alcohol + CO2
Explanation: In yeast fermentation, sugars are converted into ethyl alcohol (ethanol) and carbon dioxide (CO2) in the absence of oxygen.
Correct answer: Ethyl alcohol + CO2- A. Glycolysis
- B. Anaerobic respiration
- C. Aerobic respiration
- D. All of these
Explanation: Lactic acid is produced during anaerobic respiration, specifically through lactic acid fermentation.
Correct answer: Anaerobic respiration- A. Oxygen
- B. Carbon dioxide
- C. Water
- D. All of these
Explanation: The electron transport chain (ETC) is the final stage of cellular respiration.
Correct answer: Water- A. ATP
- B. Carbon dioxide
- C. Water
- D. Both ATP and Water
Explanation: The correct answer is 'Both ATP and Water.' The Electron Transport Chain (ETC) is the final stage of cellular respiration where the…
Correct answer: Both ATP and Water- A. Cytochrome c oxidase
- B. Complex I (NADH: ubiquinone oxidoreductase)
- C. Complex III (Cytochrome bc1 complex)
- D. Complex IV (Cytochrome c oxidase)
Explanation: Coenzyme Q, or ubiquinone, plays a crucial role in the electron transport chain.
Correct answer: Complex III (Cytochrome bc1 complex)- A. Cytochrome c
- B. Coenzyme Q
- C. NADH
- D. Cytochrome a
Explanation: In the electron transport chain, cytochrome b is reduced by receiving electrons from coenzyme Q (ubiquinone) at complex III.
Correct answer: Coenzyme Q- A. Inner membrane of mitochondria
- B. Outer membrane of mitochondria
- C. Thylakoid membrane
- D. Both A and C
Explanation: In eukaryotic cells, the inner membrane of mitochondria is the site where the majority of the Electron Transport Chain takes place.
Correct answer: Inner membrane of mitochondria- A. NADPH
- B. CO2
- C. ATP
- D. Glucose
Explanation: As a result of the Calvin cycle, the energy-rich organic compound produced is glucose.
Correct answer: Glucose- A. ATP
- B. NADPH
- C. FAD
- D. Acetyl CoA
Explanation: Oxaloacetate combines with acetyl-CoA to enter the Krebs cycle again. The Krebs cycle, also known as the citric acid cycle or TCA cycle…
Correct answer: Acetyl CoA- A. Krebs cycle
- B. Electron transport chain
- C. Glycolysis
- D. Pyruvate oxidation
Explanation: Glycolysis is a metabolic pathway that occurs in the cytoplasm of cells and is responsible for the breakdown of glucose into two molecules…
Correct answer: Glycolysis- A. Glycolysis and pentose pathway
- B. Pentose pathway only
- C. Glycolysis only
- D. Krebs cycle
Explanation: Glycolysis is a metabolic pathway that occurs in the cytoplasm of cells and is responsible for the breakdown of glucose into two molecules…
Correct answer: Glycolysis only- A. Intermembrane space
- B. Outer membrane
- C. Matrix
- D. Inner membrane
Explanation: The inner mitochondrial membrane is the site where ATP synthase is located.
Correct answer: Inner membrane- A. CO2 and H2O
- B. CO2, H2O and ATP
- C. C6H12O6 and H2O
- D. None
Explanation: Respiration in plants involves the oxidation of glucose to produce energy, with carbon dioxide (CO2) and water (H2O) as byproducts.
Correct answer: CO2, H2O and ATP- A. Molecules of glucose
- B. ATP
- C. Molecules of fructose
- D. Water
Explanation: Oxidative phase is pay-off phase in which not only ATPs are produced through substrate level phosphorylation but it also produces NADH…
Correct answer: ATP- A. Pyruvate
- B. CO2 and H2O
- C. CO2
- D. Lactic acid
Explanation: The correct answer is CO2. The citric acid cycle, also known as the Krebs cycle, plays a crucial role in cellular respiration.
Correct answer: CO2- A. 4
- B. 5
- C. 6
- D. 2
Explanation: Acetyl CoA (2-carbon compound) and a water molecule combine with oxaloacetate (4-carbon compound) to form a 6-carbon rnmpound called…
Correct answer: 4- A. Glycolysis
- B. Light dependent phase
- C. Krebs cycle
- D. None
Explanation: Glycolysis is the correct answer because it begins with the investment of 2 ATP molecules to phosphorylate glucose, which is necessary to…
Correct answer: Glycolysis