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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1,378 questions · page 66 of 69

  • A. Reduction of CO2
  • B. Regeneration of CO2 acceptor
  • C. Fixation of CO2
  • D. Regeneration of RuBP

Explanation: In first phase CO2 is condensed with RuBP in presence of Rubisco. It is called fixation of CO2.

Correct answer: Fixation of CO2
  • A. Alcoholic fermentation
  • B. Respiratory electron transport chain
  • C. Lactic acid fermentation
  • D. Alcoholic and lactic acid fermentation

Explanation: Both alcoholic fermentation and lactic acid fermentation occur in absence of oxygen. It is also called anaerobic respiration.

Correct answer: Alcoholic and lactic acid fermentation
  • A. CO2
  • B. CO2 and water
  • C. H2O
  • D. CO2 and energy

Explanation: These are the end products of aerobic respiration along with energy.

Correct answer: CO2 and water
  • A. Oxidation process
  • B. Redox process
  • C. A reduction process
  • D. Decarboxylation process

Explanation: Based on the explanations provided, the correct answer to the question is option A) Oxidation process.

Correct answer: Oxidation process
  • A. ATP to glucose
  • B. G3P to ATP
  • C. ATP to fructose
  • D. ATP to G.3.P

Explanation: As a result Glucose 6-phosphate is formed.

Correct answer: ATP to glucose
  • A. 1
  • B. 2
  • C. 3
  • D. 2, 3

Explanation: Step 2 involves rearrangement i.e. formation of Fructose 6-phosphate from glucose 6-phosphate; and 3 involves ATP phosphorylation.

Correct answer: 2, 3
  • A. Phosphoglucokinase
  • B. Pyruvate decarboxylase
  • C. Phosphofructokinase
  • D. Pyruvate dehydrogenase

Explanation: If pyruvate decarboxylase is inhibited acetate formation and subsequently Acetyl Co. A formation will be stopped.

Correct answer: Pyruvate decarboxylase
  • A. Electron transport chain
  • B. Non-cyclic photophosphorylation
  • C. Cyclic photophosphorylation
  • D. Z - scheme

Explanation: It is respiratory electron transport chain also called oxidative phosphorylation.

Correct answer: Electron transport chain
  • A. Stroma of chloroplast
  • B. Grana chloroplast
  • C. Matrix of mitochondria
  • D. Inner membrane of mitochondria

Explanation: "The explanation for this question will be added soon!".

Correct answer: Grana chloroplast
  • A. Water is reduced and CO2 is oxidized
  • B. Water is oxidized and CO2 is reduced
  • C. Both CO2 and Water are oxidized
  • D. Both CO2 and Water are reduced

Explanation: Photosynthesis is an oxidation - reduction process in which water is oxidized and CO2 is reduced.

Correct answer: Water is oxidized and CO2 is reduced
  • A. Reduction
  • B. Dehydration
  • C. Dephosphorylation
  • D. Oxidative decarboxylation

Explanation: The formation of Acetyl-CoA from pyruvic acid is the result of its oxidative decarboxylation.

Correct answer: Oxidative decarboxylation
  • A. Cytochrome b
  • B. Cytochrome c
  • C. Cytochrome a
  • D. NADH

Explanation: NADH is a molecule that helps cells produce energy. It is made in the mitochondria, which are tiny organs inside cells.

Correct answer: NADH
  • A. 2ATP
  • B. 3ATP
  • C. 4ATP
  • D. 6ATP

Explanation: Every molecule of NADH fed into the electron transport chain (ETC) produces 3 ATP.NADH is a coenzyme that carries electrons from the Krebs…

Correct answer: 3ATP
  • A. NADPH2
  • B. ATP
  • C. ATP and NADPH2
  • D. RuBP

Explanation: Light energy is converted into chemical energy through the formation of ATP and NADPH.

Correct answer: ATP and NADPH2
  • A. Plastoquinone, Cytochrome complex, Ferredoxin
  • B. Plastocyanin, Cytochrome complex, Plastoquinone
  • C. Ferredoxin, Plastocyanin, Plastoquinone
  • D. Cytochrome complex, Plastocyanin, Ferredoxin

Explanation: The cytochrome b6f complex is a protein complex that facilitates the transfer of electrons between plastoquinone and plastocyanin…

Correct answer: Cytochrome complex, Plastocyanin, Ferredoxin
  • A. 6
  • B. 4
  • C. 5
  • D. 8

Explanation: Out of 6 molecules of G3P only one leaves the calvin cycle.

Correct answer: 6
  • A. Glycolysis
  • B. Pyruvic acidoxidation
  • C. Krebs cycle
  • D. Respiratory chain

Explanation: The respiratory chain, also known as the electron transport chain (ETC), is a critical component of cellular respiration in eukaryotic…

Correct answer: Respiratory chain
  • A. Acetyl-coenzyme A.
  • B. Citrate
  • C. Coenzyme A
  • D. Ethanol

Explanation: Acetyl-Coenzyme A (acetyl-CoA) is a crucial molecule in cellular metabolism, serving as a key intermediate in various biochemical…

Correct answer: Acetyl-coenzyme A.
  • A. 1
  • B. 2
  • C. 3
  • D. 4

Explanation: 1 mole of carbon dioxide are produced by the complete oxidation of 1 mole of pyruvate.

Correct answer: 3
  • A. Acetyl coenzyme A
  • B. ATP
  • C. Pyruvate
  • D. Reduced NAD

Explanation: In biology, ATP is a molecule that carries energy within cells. It is often referred to as the "energy currency" of the cell because it…

Correct answer: ATP