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. Stroma
- B. Cristae
- C. Thylakoids
- D. Chlorophyll
Explanation: The correct part of the chloroplast that releases oxygen is the thylakoid because this is where the light-dependent reactions of…
Correct answer: Thylakoids- A. Electron transfer
- B. Release of O2
- C. Photolysis of H2O
- D. Release of H2
Explanation: During the light reaction of photosynthesis, light energy is absorbed by chlorophyll, leading to the excitation of electrons that move…
Correct answer: Release of H2- A. Photosynthetic enzyme
- B. Carbohydrates
- C. Water
- D. Carbon dioxide
Explanation: The correct source of oxygen released during photosynthesis is water because it is split in the light-dependent reactions through a…
Correct answer: Water- A. Rubisco
- B. Nitrogenase
- C. Invertase
- D. Catalase
Explanation: Rubisco is the most abundant enzyme on Earth, primarily due to its critical role in the Calvin cycle of photosynthesis, where it…
Correct answer: Rubisco- A. NADP
- B. FADH2
- C. H2O
- D. ATP
Explanation: Water is the correct source of hydrogen atoms for glucose synthesis because, during photosynthesis, it is split in the light-dependent…
Correct answer: H2O- A. Non-cyclic photophosphorylation
- B. Cyclic photophosphorylation
- C. Non-photochemical quenching chain
- D. Photorespiratory electron transport
Explanation: The correct electron transport chain in photosynthesis is non-cyclic photophosphorylation.
Correct answer: Non-cyclic photophosphorylation- A. Cyclic photophosphorylation
- B. Oxidative phosphorylation
- C. Photolysis of water
- D. Non-cyclic photophosphorylation
Explanation: In photosynthesis, Photosystem I is primarily involved in cyclic photophosphorylation, which is the correct option.
Correct answer: Cyclic photophosphorylation- A. Four
- B. Six
- C. Eight
- D. Two
Explanation: The Calvin cycle is integral to photosynthesis, as it incorporates carbon dioxide into organic molecules.
Correct answer: Six- A. Chlorophyll
- B. Water molecules
- C. O2
- D. RuBP
Explanation: The correct answer is chlorophyll. Chlorophyll is the green pigment in chloroplasts responsible for absorbing light energy, which is vital…
Correct answer: Chlorophyll910. In photosynthesis energy from the light reaction to the dark reaction is transferred in the form of:
- A. ADP
- B. AMP
- C. NADPH
- D. Chlorophyll
Explanation: In photosynthesis, the energy from the light reactions is transferred to the dark reactions in the form of NADPH.
Correct answer: NADPH- A. 24H+
- B. 12H+
- C. 6H+
- D. 1H+
Explanation: Each water molecule can release only one proton when it ionises. Therefore, twelve water molecules will release a total of 12 protons.
Correct answer: 12H+- A. Aerobic respiration
- B. Photosynthesis
- C. Nitrogen fixation
- D. Transpiration
Explanation: The main form of respiration in plants is aerobic respiration. This process breaks down glucose in the presence of oxygen to release…
Correct answer: Aerobic respiration- A. It provides oxygen to plants
- B. It liberates energy
- C. It liberates carbon dioxide
- D. All the above
Explanation: The correct answer is B) It liberates energy. Respiration is crucial for breaking down glucose molecules to release energy, which plants…
Correct answer: It liberates energy- A. 38 molecules of ATP
- B. 2 molecules of ATP
- C. 4 molecules of ATP
- D. 18 molecules of ATP
Explanation: The total oxidation of one glucose molecule during cellular respiration produces about 38 molecules of ATP.
Correct answer: 38 molecules of ATP- A. Carbon dioxide, water, and energy
- B. Oxygen and glucose
- C. Carbon dioxide and alcohol
- D. Carbon dioxide and energy only
Explanation: The end products of respiration in plants are carbon dioxide, water, and energy.
Correct answer: Carbon dioxide, water, and energy- A. Alcoholic fermentation
- B. Lactic acid fermentation
- C. Photosynthesis
- D. Aerobic respiration
Explanation: During anaerobic respiration in plants, the correct process is alcoholic fermentation.
Correct answer: Alcoholic fermentation- A. 36
- B. 2
- C. 38
- D. 4
Explanation: During anaerobic respiration, the process of glycolysis breaks down one molecule of glucose into two molecules of pyruvate, yielding four…
Correct answer: 2- A. Carbon dioxide and ethanol
- B. Lactic acid and water
- C. Oxygen and glucose
- D. Hydrogen and methane
Explanation: When yeast ferments glucose without oxygen, it produces ethanol and carbon dioxide through alcoholic fermentation.
Correct answer: Carbon dioxide and ethanol- A. Fermentation occurs in the absence of oxygen
- B. Fermentation produces large amounts of ATP
- C. Fermentation results in the complete oxidation of glucose
- D. Fermentation produces byproducts such as lactic acid or ethanol
Explanation: Fermentation is an anaerobic process that occurs without oxygen and allows organisms to produce energy when oxygen is unavailable.
Correct answer: Fermentation produces byproducts such as lactic acid or ethanol- A. Animal cells
- B. Red blood cells
- C. Neurons
- D. Epidermal cells
Explanation: Glycolysis is a process that breaks down glucose into pyruvate in the cytoplasm of cells, producing a small amount of ATP and NADH.
Correct answer: Animal cells