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. All photosynthetic plants, green algae, and cyanobacteria
- B. Green plants and green algae only
- C. Red algae and brown algae
- D. Photosynthetic bacteria such as purple and green sulfur bacteria
Explanation: Chlorophyll b is found only in green plants and green algae, where it works alongside chlorophyll a to absorb a wider range of light…
Correct answer: Green plants and green algae only- A. Water
- B. Alcohol and organic solvents
- C. Dilute acids
- D. Alkalies
Explanation: Chlorophylls are fat-soluble pigments that dissolve in organic solvents (like alcohol, acetone, and ether) but not in water, acids, or…
Correct answer: Alcohol and organic solvents- A. Carotenes
- B. Chlorophyll b
- C. Xanthophylls
- D. All of these
Explanation: Accessory pigments are integral to photosynthesis, as they allow plants to capture a broader spectrum of light wavelengths than…
Correct answer: All of these- A. Chlorophylls - a
- B. Chlorophylls - b
- C. Carotenoids
- D. Both B and C
Explanation: Both chlorophyll b and carotenoids transfer energy to chlorophyll a during photosynthesis.
Correct answer: Both B and C- A. Carotenoids → Chlorophyll a → Chlorophyll b
- B. Chlorophyll b → Chlorophyll a → Carotenoids
- C. Carotenoids → Chlorophyll b → Chlorophyll a
- D. Chlorophyll a → Chlorophyll b → Carotenoids
Explanation: Option C is correct.The order of energy transfer is carotenoids → chlorophyll b → chlorophyll a.Chlorophyll b absorbs light energy in the…
Correct answer: Carotenoids → Chlorophyll b → Chlorophyll a- A. Absorbing excessive light energy
- B. Dissipating excessive light energy
- C. Transferring excessive light energy to chlorophyll a
- D. Both absorbing and dissipating excessive light energy
Explanation: Option D is correct because carotenoids protect chlorophyll by both absorbing and dissipating excessive light energy as heat.
Correct answer: Both absorbing and dissipating excessive light energy- A. Chlorophyll - a
- B. Human eyes
- C. Chlorophyll - b
- D. All of these
Explanation: Option D is correct because carotenoids are versatile pigments that provide protection against intense light across different systems.
Correct answer: All of these- A. Blue part of the spectrum
- B. Red part of the spectrum
- C. Blue and Red parts of spectrum
- D. White and red part of the spectrum
Explanation: Option C is correct.The absorption spectrum for chlorophyll indicates that absorption is maximum in the blue and red parts of the…
Correct answer: Blue and Red parts of spectrum- A. Two peaks and one valley
- B. One peak and one valley
- C. Two peaks and two valleys
- D. One peak and two valleys
Explanation: The most accurate representation of the absorption spectrum of chlorophylls is two peaks and one valley.
Correct answer: Two peaks and one valley- A. Absorption spectrum of chlorophyll a
- B. Absorption spectrum of carotenoids
- C. Absorption spectrum of chlorophyll b
- D. All have broadest valleys
Explanation: Option A is correct: The absorption spectrum of chlorophyll a features the broadest valley around 520-530 nm, indicating the least…
Correct answer: Absorption spectrum of chlorophyll a- A. 453 nm and 642 nm
- B. 430 nm and 662 nm
- C. 480 nm and 520 nm
- D. 500 nm and 700 nm
Explanation: Among the given options, the most accurate ones are 453 nm and 642 nm. These wavelengths represent the two main absorption peaks of…
Correct answer: 453 nm and 642 nm- A. Oxidation of CO2 occurs
- B. Oxidation of H2O occurs
- C. Reduction of CO2 occurs
- D. Both B and C
Explanation: Option D is correct because photosynthesis is a redox process that encompasses both the oxidation of water and the reduction of carbon…
Correct answer: Both B and C- A. Two phases
- B. Four phases
- C. Three phases
- D. Many phases
Explanation: The correct answer is Option A. Photosynthesis comprises two main phases: the light-dependent reactions and the Calvin cycle.
Correct answer: Two phases- A. Dark reaction
- B. Light reaction
- C. Calvin cycle
- D. Oxidation phosphorylation
Explanation: Option B is correct.The reducing power and assimilatory power are synthesized during the light-dependent reactions of photosynthesis.
Correct answer: Light reaction- A. Enzymes
- B. Co-enzymes
- C. Energized electrons
- D. Both B and C
Explanation: NADPH is vital in the Calvin cycle, where it acts both as a coenzyme and a provider of energized electrons.
Correct answer: Both B and C- A. It requires darkness
- B. It does not require light
- C. It requires night period
- D. It produces darkness in the chloroplast
Explanation: The dark reaction, also known as the Calvin cycle, is called so because it does not require light directly to carry out its chemical…
Correct answer: It does not require light- A. Antenna pigments
- B. Reaction centre
- C. Photosynthetic system
- D. Photosystems
Explanation: The correct answer is photosystems. Photosynthetic pigments are organized into clusters known as photosystems, which are crucial for the…
Correct answer: Photosystems- A. Antenna complex
- B. Reaction complex
- C. Both A and B
- D. Primary electron acceptor
Explanation: Each photosystem contains an antenna complex and a reaction center. The antenna complex is responsible for capturing light energy using…
Correct answer: Both A and B- A. One molecule of chlorophyll a and a primary electron acceptor
- B. Many molecules of chlorophyll a and primary electron acceptor
- C. One or more molecules of chlorophyll a and the primary electron acceptor
- D. Chlorophyll a, chlorophyll b, and the primary electron acceptor
Explanation: The reaction center of a photosystem is crucial for the initial steps of photosynthesis.
Correct answer: One or more molecules of chlorophyll a and the primary electron acceptor- A. P680 and P700
- B. PS-I and PS-II
- C. PS-II and PS-I
- D. Photo system alpha and photo system beta
Explanation: The correct answer is PS-I and PS-II. Photosystem I (PS-I) was discovered before Photosystem II (PS-II), which is why they are named in…
Correct answer: PS-I and PS-II