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. Calvin cycle
- B. Hatch-slack
- C. TCA-cycle
- D. All of these
Explanation: The high efficiency of carbon dioxide (CO2) fixation in C4 plants, including tropical plants like sugarcane, is indeed associated with the…
Correct answer: Hatch-slack- A. Cytosol
- B. Mitochondria
- C. Nucleus
- D. All of these
Explanation: Mitochondria is the only place where ATP can be synthesized as the compartmentalization within the mitochondria provides an efficient and…
Correct answer: Mitochondria- A. Chloroplast
- B. Grana
- C. Thylakoid
- D. Stroma
Explanation: The light reactions of photosynthesis indeed take place in the thylakoid membranes within the chloroplasts of plant cells.
Correct answer: Thylakoid384. The part of the chlorophyll molecule is embedded in the core of the thylakoid membrane, which is?
- A. Hydrophilic
- B. Hydrophobic
- C. Both A and B
- D. None of these
Explanation: The part of the chlorophyll molecule that is embedded in the core of the thylakoid membrane is the hydrophobic phytol tail.
Correct answer: Hydrophobic- A. Neutrophil cells
- B. Basophil cells
- C. Mesophyll cells
- D. All of these
Explanation: Option C is correct. Mesophyll cells are found in the spongy and palisade layers of the leaf, where they are responsible for…
Correct answer: Mesophyll cells- A. Krebs cycle
- B. Calvin Cycle
- C. Galvin cycle
- D. Glycolysis
Explanation: The dark reaction in photosynthesis, where sugars are synthesized, is known as the Calvin Cycle or the light-independent reactions.
Correct answer: Calvin Cycle- A. Mechanical energy
- B. Physical energy
- C. Chemical energy
- D. All of these
Explanation: The correct answer is Option C: Chemical energy. ATP (adenosine triphosphate) is a critical molecule in energy transfer within cells.
Correct answer: Chemical energy- A. Coenzyme C
- B. Coenzyme Q
- C. Coenzyme b
- D. Coenzyme a
Explanation: In the electron transport chain (ETC), NADH acts as an electron donor, not an oxidizer.
Correct answer: Coenzyme Q- A. Non-cyclic electron flow
- B. Cyclic electron flow
- C. Circular electron flow
- D. Both b and c
Explanation: The most common electron transport chain in photosynthesis is the non-cyclic electron flow.
Correct answer: Non-cyclic electron flow- A. Brain
- B. Heart
- C. Liver
- D. Muscles
Explanation: Lactic acid fermentation primarily occurs in skeletal muscles under anaerobic conditions, such as during intense exercise when oxygen…
Correct answer: Muscles- A. Pyruvic acid
- B. Acetyl CoA
- C. Carbon dioxide
- D. Both A and B
Explanation: Option B is correct since, for pyruvate, the product of glycolysis, to enter the next pathway, it must undergo several changes to become…
Correct answer: Acetyl CoA- A. 10 %
- B. 50 %
- C. 1-2 %
- D. 0.3 to 0.4 %
Explanation: Option C is correct since stomata are the microscopic pores on leaf surfaces that facilitate gas exchange with the atmosphere, namely…
Correct answer: 1-2 %- A. 6
- B. 5
- C. 3
- D. 8
Explanation: In the Calvin cycle, 3 molecules of carbon dioxide are fixed by an enzyme called RuBisCO, resulting in 6 molecules of G3P.
Correct answer: 6- A. Stomata
- B. Grana
- C. Porphyrin ring
- D. Photons
Explanation: Stomatal opening is the place where gaseous exchange occurs in the plant.
Correct answer: Stomata- A. Pq
- B. Pm
- C. Pt
- D. Po
Explanation: Plastoquinone, abbreviated as Pq, is a crucial electron carrier in the light-dependent reactions of photosynthesis.
Correct answer: Pq- A. Water
- B. Hydrogen present in soil
- C. Hydrogen sulphate
- D. Hydrogen sulphide
Explanation: Cyanobacteria are the first photosynthetic organisms. They used hydrogen sulfide as source of hydrogen.
Correct answer: Hydrogen sulphide- A. Synthesis of complex compounds
- B. Active transport
- C. Muscular contraction
- D. All of these
Explanation: The correct answer is d) All of these. ATP is the universal energy currency of the cell, and it is utilized in numerous cellular…
Correct answer: All of these- A. Light dependent reaction
- B. Light independent reaction
- C. Both of these
- D. None of above
Explanation: The light-independent reaction, also known as the Calvin cycle or the dark reactions, is the second stage of photosynthesis.
Correct answer: Light independent reaction- A. Cytochrome a
- B. Cytochrome a3
- C. Cytochrome c1
- D. Cytochrome b
Explanation: The respiratory chain electron carrier that directly binds oxygen is cytochrome a3.
Correct answer: Cytochrome a3- A. Antenna complex
- B. Reaction center
- C. Photosystem
- D. None of these
Explanation: The correct answer is the antenna complex. It is specifically designed to gather light by capturing photons through its pigments, such as…
Correct answer: Antenna complex