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. ADP
- B. Reduced FAD
- C. Citric acid
- D. Pyruvate
Explanation: The end product of glycolysis is two molecules of pyruvate(3C compound).
Correct answer: Pyruvate1202. FADH2 is produced in?
- A. Glycolysis
- B. Pyruvic acid oxidation
- C. Krebs cycle
- D. None
Explanation: The Krebs cycle, also known as the citric acid cycle, is the stage of cellular respiration where FADH2 is produced.
Correct answer: Krebs cycle- A. 5%
- B. 2%
- C. 7%
- D. 10%
Explanation: In anaerobic respiration, the process primarily involves glycolysis followed by fermentation, which yields only a small amount of ATP…
Correct answer: 2%- A. Glycolysis
- B. Cellular respiration
- C. Fermentation
- D. None of the above
Explanation: This is the correct answer. Glycolysis is the metabolic pathway that breaks down one molecule of glucose into two molecules of pyruvate.
Correct answer: Glycolysis- A. Cytoplasm
- B. Mitochondria
- C. Nucleus
- D. Endoplasmic reticulum
Explanation: This is the correct answer. Glycolysis, the initial stage of cellular respiration, occurs in the cytoplasm of the cell.
Correct answer: Cytoplasm- A. Stroma of chloroplast
- B. Guard cells of stomata
- C. Thylakoid membrane of chloroplast
- D. Cytoplasm of leaf cell
- E. None of the above
Explanation: The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage…
Correct answer: Thylakoid membrane of chloroplast- A. Dawn
- B. Noon
- C. Dusk
- D. Dawn and dusk
Explanation: At dawn and dusk, when light intensity is low, the rate of photosynthesis and respiration may, for a short time, equal one another.
Correct answer: Dawn and dusk- A. Orange
- B. Grey
- C. Yellow
- D. Blue-Green
- E. Yellow-Green
Explanation: In paper chromatography, xanthophylls are pigments that are often responsible for giving a yellow color.
Correct answer: Yellow- A. Citrate
- B. Alpha-ketoglutarate
- C. Succinate
- D. Fumarate
- E. Oxaloacetate
Explanation: In the Krebs cycle, also known as the citric acid cycle, the formation of succinate involves a series of chemical reactions, and…
Correct answer: Succinate- A. Fe2+
- B. Mg2+
- C. Mn2+
- D. Ca2+
Explanation: The main difference between the chlorophyll molecule and the heme group of hemoglobin is that chlorophyll contains a magnesium ion (Mg2+)…
Correct answer: Mg2+- A. ATP
- B. FAD
- C. FADH
- D. ADP
Explanation: During glycolysis, the oxidation of one molecule of 3-phosphoglyceraldehyde (PGAL or G3P, which stands for glyceraldehyde-3-phosphate)…
Correct answer: ATP- A. Energy
- B. Electrons
- C. Hydrogen protons
- D. All of above
Explanation: When a molecule undergoes reduction, it gains electrons, hydrogen/protons, and often energy.
Correct answer: All of above- A. Stroma and grana of chloroplast respectively
- B. Grana and stroma of chloroplast respectively
- C. Grana only
- D. Stroma only
Explanation: The light reactions occur in the thylakoid membranes, while the dark reactions (Calvin Cycle) take place in the stroma of the…
Correct answer: Stroma and grana of chloroplast respectively- A. T. W. Engelmann
- B. Malleus
- C. T. W. Inws
- D. W. Stapes
Explanation: The first action spectrum was obtained by German biologist T.W.England in 1833.
Correct answer: T. W. Engelmann- A. Leaves
- B. Stems
- C. Roots
- D. Branches
Explanation: The leaves are the main sites of photosynthesis in plants, where the chloroplasts capture sunlight and convert it into energy and glucose…
Correct answer: Leaves- A. Stroma
- B. Chloroplast envelope
- C. Thylakoid membranes
- D. The intergrana
Explanation: Each granum is made up of coin-like thylakoids, whose membranes have photosystems.
Correct answer: Thylakoid membranes- A. Leaves respire utilizes O2 and releases CO.
- B. Photosynthesis and respiration occur at the same rate. So there is no net exchange of gases between the atmosphere and plants.
- C. The rate of photosynthesis increases, and so does the O2 production, with a net release of oxygen coupled with the uptake of CO2
- D. The rate of respiration becomes more than the rate of photosynthesis.16 Net yield of H2O in Photosynthesis is
Explanation: "The explanation for this question will be added soon!".
Correct answer: Photosynthesis and respiration occur at the same rate. So there is no net exchange of gases between the atmosphere and plants.- A. A 5C carbohydrate accepts carbon dioxide and is then reduced by NADPH derived from photosynthesis
- B. A 3Ccarbohydrate is regenerated and reduced by hydrogen molecules derived from photophosphorylation
- C. Photolysis uses light to produce reduced NADP and oxygen which are used to reduce a 3Ccarbohydrate
- D. Photolysis produces NADPH and ATP which are used to reduce a 5C cartediadrate
Explanation: "The explanation for this question will be added soon!".
Correct answer: Photolysis uses light to produce reduced NADP and oxygen which are used to reduce a 3Ccarbohydrate- A. 45
- B. 35°C
- C. 15°C
- D. 25°C
Explanation: Despite the fact that the stomata open in response to light, they may close on a hot day in order to conserve water.
Correct answer: 45- A. p680,p700, water, NADP
- B. Water, p700, NADP, p68
- C. p700, p680, NADP, water
- D. Water, p680, p700, NADP
Explanation: In the presence of light the photolysis of water occurs in the water splitting centre within photosystem II, the electrons released are…
Correct answer: Water, p680, p700, NADP