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. Preparatory phase
- B. Lactic acid fermentation
- C. Payoff phase
- D. Carbon fixation
Explanation: A. This is the first step of glycolysis.B. In absence of oxygen, pyruvic acid is converted into lactic acid.
Correct answer: Payoff phase- A. 6.1
- B. 6.3
- C. 7.1
- D. 7.3
Explanation: Breaking of the terminal phosphate of ATP releases about 7.3 Kcal of energy.
Correct answer: 7.3- A. Absorption of CO2
- B. Absorption of O2
- C. Reflection of pigments
- D. Absorption of different wavelengths
Explanation: Spectrophotometer is a device that is designed to measure the absorption of different wavelength of light by substance across a range of…
Correct answer: Absorption of different wavelengths- A. Absorption spectrum
- B. Action spectrum
- C. Broad spectrum
- D. Narrow spectrum
Explanation: The graph showing relative effectiveness of different wavelengths of light in driving photosynthesis is called action spectrum.
Correct answer: Action spectrum- A. 670 nm
- B. 540 nm
- C. 430 nm
- D. 750 nm
Explanation: Wavelength of visible light varies from 380 nm to 750 nm. This spectrum contains seven different colors.
Correct answer: 430 nm- A. Cyanobacteria
- B. Purple sulphur bacteria
- C. Plants
- D. Algae
Explanation: purple sulphur bacteria use hydrogen sulphide as proton donor. Rest of organisms use water as proton donor for photosynthesis.
Correct answer: Purple sulphur bacteria- A. Porphyrin ring
- B. Phytol tail
- C. Pyrrole ring
- D. Hydrophobic part
Explanation: In porphyrin rings, the central atom is typically a metal ion, and one common metal ion found in porphyrin rings is magnesium…
Correct answer: Porphyrin ring- A. Chl.a→Chl.b→Carotenoids
- B. Carotenoids→Chl.b→Chl.a
- C. Chl.b→Carotenoids→Chl.a
- D. In any direction
Explanation: Carotenoids and chloroph II 'b' are called accessory pigments because they absorb light and transfer the energy to chlorophyll a, which…
Correct answer: Carotenoids→Chl.b→Chl.a- A. Stroma
- B. Thylakoid membrane
- C. Thylakoid surface
- D. Thylakoid lumen
Explanation: Chlorophyll molecule has a long hydrocarbons tail which is attached to one of the pyrrole rings of chlorophyll molecules and is embedded…
Correct answer: Thylakoid membrane- A. Convert light energy into chemical energy
- B. Protect chlorophyll
- C. Transfer energy
- D. Protect human eye
Explanation: Transfer of energy, broadening the spectrum, protection of chlorophyll molecules and eyes are the functions of carotcnoids.
Correct answer: Convert light energy into chemical energy- A. P680
- B. P700
- C. P730
- D. P660
Explanation: There are two types of photosystems named as PS-I and PS-II. PS-I has type of chlorophyll that absorbs maximum wavelenght of 700 nm while…
Correct answer: P680- 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: Photosytem II is involved in the photolysis of water (as a result oxygen is evolved) If photosystem II is absent in organism, oxygen will…
Correct answer: To test for liberation of O2 in the light- A. NADP+ to ferredoxin
- B. Ferredoxin to NADP+
- C. ADP to ATP
- D. Cytochrome complex to NADP+
Explanation: NADP+ reductase transfers electron from ferredoxin to NADP+.
Correct answer: Ferredoxin to NADP+- A. Does not require light directly
- B. It uses ATP
- C. Also called Z-scheme
- D. G3P is produced
Explanation: Z-scheme is another name use for light dependent reaction of photosynthesis because electrons move in zigzag fashion.
Correct answer: Also called Z-scheme- A. Glycolysis
- B. Calvin cycle
- C. Krebs cycle
- D. Light dependent reactions
Explanation: The Calvin cycle, also known as the Calvin-Benson cycle, is a series of biochemical reactions that take place in the stroma of…
Correct answer: Calvin cycle- A. One
- B. Six
- C. Two
- D. Twelve
Explanation: Since 6 molecules of NADPH are used for the synthesis of 1 G3P in Calvin cycle, so for the synthesis of one glucose molecule that requires…
Correct answer: One- A. Initial incorporation of 3 CO2 molecules
- B. Production of 3 carbon G3P
- C. Production of 3 carbon 3PGA
- D. Cycle has 3 steps
Explanation: Because the product of initial carbon fixation is a three- carbon compound, the Calvin cycle is also known as C3 path
Correct answer: Production of 3 carbon 3PGA- A. 9ATP + 6NADPH2
- B. 18ATP + 12NADPH2
- C. 6ATP + 9NADPH2
- D. 3ATP + 3NADPH2
Explanation: The chemical equation of dark reaction is: 3CO2 + 6NADPH + 9ATP → (CH2O)3 + 6NAPD +9ADP+ 9Pi + 3H20 (Carbohydrate) For every molecule of…
Correct answer: 9ATP + 6NADPH2- A. Bacteria
- B. Yeast
- C. Skeletal muscles
- D. All A,B,C
Explanation: Aerobic organisms use oxygen to produce energy for their metabolism. Almost all types of cells are adapted to do respiration without oxygen.
Correct answer: All A,B,C- A. ATP
- B. Oxygen
- C. NADH
- D. Glucose
Explanation: Cellular respiration is a process in which energy is released in the form of ATP due to catabolism of organic substance.
Correct answer: ATP