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. Cytoplasmic matrix
- B. Leucoplasts
- C. Mitochondria
- D. Chloroplasts
Explanation: The correct answer is chloroplast. Chloroplasts are the sites of photosynthesis in plant cells, encompassing both the light-dependent and…
Correct answer: Chloroplasts- A. 36
- B. 12
- C. 38
- D. 18
Explanation: The Benson-Calvin cycle, which occurs in the stroma of chloroplasts, is the light-independent phase of photosynthesis.
Correct answer: 18- A. Glucose from carbon dioxide and water
- B. ATP from ADP and inorganic phosphate
- C. Oxygen from water molecules
- D. NADPH from NADP⁺ and hydrogen ions
Explanation: During photophosphorylation, light energy is captured by chlorophyll and other pigment molecules in the thylakoid membranes of…
Correct answer: ATP from ADP and inorganic phosphate- A. ATP
- B. NADPH2
- C. O2
- D. All of these
Explanation: In cyclic photophosphorylation, electrons released by chlorophyll return to the same chlorophyll molecule, and ATP is produced.
Correct answer: ATP- A. Glycolysis
- B. Krebs cycle
- C. Pyruvic acid oxidation
- D. Electron transport chain
Explanation: Pyruvic acid oxidation does not directly produce ATP. Instead, it involves the conversion of pyruvate into acetyl-CoA, yielding NADH but…
Correct answer: Pyruvic acid oxidation- A. Robert Hill
- B. C. Calvin
- C. T.W. Engelmann
- D. Hatch and Slack
Explanation: The correct answer is T.W. Engelmann. In 1883, Engelmann conducted experiments using a prism to disperse light across a filament of algae…
Correct answer: T.W. Engelmann- A. 2 electrons, 1 proton
- B. 2 Electrons 2 protons
- C. 1 Electron 2 protons
- D. 1 Electron 1 proton
Explanation: The conversion of NAD+ into NADH is a reduction process that requires the addition of 2 electrons and 1 proton.
Correct answer: 2 electrons, 1 proton- A. 1,3-Bisphosphoglycerate
- B. Ribulose-1,5-bisphosphate
- C. 3-phosphoglycerate
- D. Glyceraldehyde-3-phosphate
Explanation: The molecule that is reduced by accepting hydrogen in the Calvin cycle is 1,3-bisphosphoglycerate.
Correct answer: 1,3-Bisphosphoglycerate- A. Lipids
- B. Carbohydrates
- C. ATP
- D. Proteins
Explanation: ATP (adenosine triphosphate) is the immediate source of energy for cellular metabolism because it directly powers cellular activities by…
Correct answer: ATP- A. Kelps
- B. Spirogyra
- C. Wheat
- D. Purple sulphur bacteria
Explanation: The correct answer is the D: purple sulfur bacteria these bacteria do not contain chlorophyll a; they utilise bacteriochlorophylls for…
Correct answer: Purple sulphur bacteria- A. Metabolism
- B. Photosynthesis
- C. Photorespiration
- D. Bioenergetics
Explanation: The correct answer is bioenergetics. Bioenergetics is dedicated to understanding how organisms acquire, transform, and utilize energy…
Correct answer: Bioenergetics- A. Types of photosystems involved
- B. Product form
- C. Time duration
- D. All of these
Explanation: In cyclic and non-cyclic photophosphorylation, the photosystems involved are different.
Correct answer: All of these- A. It acts as an accessory pigment
- B. It reflects green light
- C. It absorbs light mainly in the blue and red regions
- D. It is the primary pigment in photosynthesis
Explanation: Chlorophyll b acts as an accessory pigment, helping chlorophyll a by capturing additional light energy and transferring it for use in…
Correct answer: It is the primary pigment in photosynthesis- A. Protein
- B. Nucleic acid
- C. Lipid
- D. Carbohydrate
Explanation: Ribulose 1,5-bisphosphate (RuBP) is indeed a carbohydrate. It is a five-carbon sugar (ketopentose) with two phosphate groups and serves as…
Correct answer: Carbohydrate- A. 2 carbon atoms
- B. 3 carbon atoms
- C. 4 carbon atoms
- D. 5 carbon atoms
Explanation: The first stable compound formed during the light-independent reactions of photosynthesis contains three carbon atoms.
Correct answer: 3 carbon atoms- A. Cristae
- B. Mitochondrial matrix
- C. Inter-membrane space
- D. Cytoplasm
Explanation: The correct answer is cristae. Cristae are the folds within the inner mitochondrial membrane that house the enzymes for the electron…
Correct answer: Cristae- A. One
- B. Two
- C. Four
- D. Three
Explanation: The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions used by all aerobic organisms to generate energy…
Correct answer: Two- A. C3 pathway
- B. Sugar synthesis phase
- C. Dark reactions
- D. All of these
Explanation: The Calvin cycle is known by several names that highlight its different characteristics and roles in photosynthesis: It is called the C3…
Correct answer: All of these- A. Chlorophyll b
- B. Chlorophyll c
- C. Chlorophyll d
- D. Chlorophyll a
Explanation: Chlorophyll a is the correct answer because it is the most abundant and primary photosynthetic pigment in plants, algae, and…
Correct answer: Chlorophyll a720. In which stage of aerobic respiration are 2-carbon molecules oxidized completely to carbon dioxide?
- A. Glycolysis
- B. Krebs cycle
- C. ETC
- D. Calvin cycle
Explanation: The correct answer is the Krebs cycle. This cycle occurs in the mitochondria and is responsible for the complete oxidation of acetyl-CoA…
Correct answer: Krebs cycle