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.
Last updated
Read the Bioenergetics notesFree MDCAT chapter notes with key terms1,378 questions · page 33 of 69
- A. Carbon dioxide
- B. Water
- C. Sunlight
- D. All of these
Explanation: The correct answer is Option: All of these. Photosynthesis in green plants requires carbon dioxide, water, and sunlight.
Correct answer: All of these- A. Glucose and oxygen
- B. Carbon dioxide and water
- C. ATP and NADPH
- D. Proteins and lipids
Explanation: The main products of photosynthesis in green plants are glucose and oxygen, which provide energy for the plant and oxygen for other…
Correct answer: Glucose and oxygen- A. Absorption of CO2
- B. Absorption of O2
- C. Reflection of pigments
- D. Absorption of different wavelengths
Explanation: A spectrophotometer measures the absorption of various wavelengths of light.
Correct answer: Absorption of different wavelengths- A. Absorption spectrum
- B. Action spectrum
- C. Broad spectrum
- D. Narrow spectrum
Explanation: The action spectrum is the correct answer because it directly measures how effective different wavelengths of light are in facilitating…
Correct answer: Action spectrum- A. Water
- B. CO2
- C. Glucose
- D. Oxidation of chlorophyll
Explanation: The oxygen released during photosynthesis originates from water molecules.
Correct answer: Water- A. 670 nm
- B. 540 nm
- C. 430 nm
- D. 750 nm
Explanation: In the visible light spectrum, chlorophyll pigments in plants absorb light most effectively in the blue (around 430 nm) and red (around…
Correct answer: 430 nm- A. Cyanobacteria
- B. Purple sulphur bacteria
- C. Plants
- D. Algae
Explanation: Purple sulfur bacteria use hydrogen sulfide (H₂S) as their proton and electron donor, distinguishing them from other groups like…
Correct answer: Purple sulphur bacteria- A. Red to orange
- B. Yellow green
- C. Yellow red
- D. Blue violet
Explanation: Carotenoids are pigments that appear yellow, orange, or red because they reflect those colors.
Correct answer: Blue violet- A. Porphyrin ring
- B. Phytol tail
- C. Pyrrole ring
- D. Hydrophobic tail
Explanation: The correct answer is the porphyrin ring. In chlorophyll, the porphyrin ring is a crucial component where magnesium acts as the central…
Correct answer: Porphyrin ring- A. A head of phytol and a tail of four pyrrole rings
- B. A head of linked carbons and a tail of four pyrrole rings
- C. A head of four pyrrole rings and a tail of linked nitrogen
- D. It has a head of four pyrrole rings and a phytol tail
Explanation: The chlorophyll molecule consists of two main parts: a hydrophilic head and a hydrophobic tail.
Correct answer: It has a head of four pyrrole rings and a phytol tail- A. Chl.a→Chl.b→Carotenoids
- B. Carotenoids→Chl.b→Chl.a
- C. Chl.b→Carotenoids→Chl.a
- D. In any direction
Explanation: The correct sequence of energy transfer between photosynthetic pigments is carotenoids→Chl.b→Chl.a.
Correct answer: Carotenoids→Chl.b→Chl.a- A. Chlorophyll 'a' has a methyl (-CH₃) group at the C-3 position, while chlorophyll 'b' has a formyl (-CHO) group at the same position
- B. Chlorophyll 'a' absorbs light primarily at 430 nm and 662 nm, whereas chlorophyll 'b' absorbs at 453 nm and 642 nm
- C. Chlorophyll 'a' is found only in plants, while chlorophyll 'b' is found only in algae
- D. Chlorophyll 'a' participates directly in the light reactions of photosynthesis, whereas Chlorophyll 'b' acts as an accessory pigment
Explanation: Chlorophyll 'a' and 'b' differ in their chemical structure, absorption spectra, and roles in photosynthesis.
Correct answer: Chlorophyll 'a' is found only in plants, while chlorophyll 'b' is found only in algae- A. Stroma
- B. Thylakoid membrane
- C. Thylakoid surface
- D. Thylakoid lumen
Explanation: Chlorophyll molecules, including chlorophyll b, have a hydrophobic phytol tail that allows them to embed firmly into the lipid bilayer of…
Correct answer: Thylakoid membrane- A. Convert light energy into chemical energy
- B. Protect chlorophyll
- C. Transfer energy
- D. Protect human eye
Explanation: Carotenoids are accessory pigments that have several important roles, including protecting chlorophyll from damage, transferring energy to…
Correct answer: Convert light energy into chemical energy655. PS-I is named as it:
- A. Absorbs wavelength of 680 nm
- B. Discovered earlier than PS-II
- C. Absorbs the wavelength of 700 nm
- D. Slightly located upward than PS-II
Explanation: The correct answer is that PS-I is named so because it was discovered before PS-II.
Correct answer: Discovered earlier than PS-II- A. P680
- B. P700
- C. P730
- D. P660
Explanation: Photosystem II (PS II) and Photosystem I (PS I) are two distinct complexes in the light-dependent reactions of photosynthesis.
Correct answer: P680- A. Photosystem I
- B. Ferredoxin
- C. Photosystem II
- D. Cytochrome complex
Explanation: In cyclic photophosphorylation, electrons are cycled back to Photosystem I after passing through components such as ferredoxin and the…
Correct answer: Photosystem II- A. To determine if they have thylakoids in the chloroplasts
- B. To test for liberation of O₂ in the light
- C. To test for CO2 fixation in the dark
- D. To do experiments to generate an action spectrum
Explanation: Photosystem II plays a vital role in the photolysis of water, which results in the release of oxygen.
Correct answer: To test for liberation of O₂ in the light- A. Stroma
- B. Thylakoid membrane
- C. Chloroplast
- D. Leucoplast
Explanation: The light reactions of photosynthesis occur in the thylakoid membranes of the chloroplasts.
Correct answer: Thylakoid membrane- A. 1
- B. 4
- C. 2
- D. 8
Explanation: Each photon of light excites one electron in a pigment molecule, such as chlorophyll, during the light-dependent reactions of…
Correct answer: 1