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. Intermediates in photosynthesis
- B. Respiratory fuel
- C. Intermediates in cellular respiration
- D. Component of DNA and RNA
Explanation: Ribulose is a type of sugar and is involved in several biological processes, particularly in the context of photosynthesis.
Correct answer: Intermediates in photosynthesis- A. Primary Electron Acceptor (PEA) to Plastoquinone (Pq)
- B. Plastoquinone (Pq) to cytochromes
- C. Cytochrome to Plastocyanin (Pc)
- D. Plastocyanin (Pc) to Photosystem I (PS I)
Explanation: When an electron leaves PSII, it is transferred first to a small organic molecule (plastoquinone, Pq), then to a cytochrome complex (Cyt)…
Correct answer: Cytochrome to Plastocyanin (Pc)- A. Stroma
- B. Granum
- C. Inner membrane
- D. Outer membrane
Explanation: Photophosphorylation takes place in the thylakoid membrane of the chloroplasts.
Correct answer: Granum- A. Phospholipids of the membrane
- B. ADP
- C. Inorganic phosphates
- D. ATP
Explanation: During the initial steps of glycolysis, ATP molecules are crucial for facilitating the phosphorylation of glucose.
Correct answer: ATP- A. Glycolysis
- B. Krebs cycle
- C. Oxidation
- D. Electron transport system
Explanation: Pyruvic acid is the end product of glycolysis, the first stage of cellular respiration.
Correct answer: Glycolysis- A. Nitrogen
- B. Oxygen
- C. Carbon monoxide
- D. Carbon dioxide
Explanation: Carbon dioxide (CO2) is fixed in the stroma of chloroplasts during the light-independent reactions, also known as the Calvin cycle or the…
Correct answer: Carbon dioxide- A. Chlorophyll a
- B. Chlorophyll b
- C. Chlorophyll c
- D. Chlorophyll d
Explanation: Chlorophyll a is found in all types of algae. Chlorophyll a is a primary photosynthetic pigment that plays a central role in capturing…
Correct answer: Chlorophyll a- A. Vitamin A
- B. Vitamin B
- C. Vitamin C
- D. Vitamin D
Explanation: Carotenoids are related to Vitamin A. They are a group of pigments that are responsible for the yellow, orange, and red colors of many…
Correct answer: Vitamin A- A. Thylakoids
- B. Grana
- C. Intergrana
- D. Stroma
Explanation: The dark reactions of photosynthesis, also known as the Calvin Cycle or light-independent reactions, take place in the stroma of the…
Correct answer: Stroma- A. CO2
- B. H2O
- C. C6H12O6
- D. CO2 and H2O
Explanation: Oxygen released into the atmosphere during photosynthesis comes from the splitting of water molecules.
Correct answer: H2O- A. Ribulose bisphosphate
- B. 6 carbon compound
- C. 5 carbon compound
- D. 3 carbon compound
Explanation: In the presence of ATP and reduced NADP (produced during the light-dependent reactions), 3-phosphoglycerate (3-PGA) is reduced to…
Correct answer: 3 carbon compound- A. Source of energy to carry out the reaction
- B. Production of organic compounds
- C. Reduction of CO2
- D. Carried out by bacteria
Explanation: Chemosynthesis and photosynthesis are both processes that produce organic compounds, but they differ in the source of energy…
Correct answer: Source of energy to carry out the reaction- A. Fe
- B. Mg
- C. Mn
- D. Ca
Explanation: The main difference between the chlorophyll molecule and the heme group of hemoglobin is that chlorophyll contains a magnesium ion (Mg2+)…
Correct answer: Mg- A. Formation of 1, 3- Bisphosphoglycerate
- B. Conversion of 1, 3- Bisphosphoglycerate to Glyceraldehyde 3- phosphate
- C. Formation of fructose 1, 6- bisphosphate from 1, 3- bisphosphoglycerate
- D. Formation of glucose from fructose bisphosphate
Explanation: In the Calvin Cycle, the reducing power from NADPH is used during the reduction phase of the cycle.
Correct answer: Conversion of 1, 3- Bisphosphoglycerate to Glyceraldehyde 3- phosphate- A. ATP
- B. NADH
- C. FADH
- D. ADP
Explanation: During glycolysis, the oxidation of one molecule of 3-phosphoglyceraldehyde (PGAL or G3P) leads to the conversion of NAD+ to NADH.
Correct answer: NADH- A. 2
- B. 7
- C. 10
- D. 20
Explanation: Lactic acid fermentation is a type of anaerobic respiration that occurs in human muscle cells when oxygen availability is limited, such as…
Correct answer: 2- A. Enzymes
- B. Hormones
- C. Lactic acid
- D. Fat
Explanation: In anaerobic respiration, when oxygen is scarce, glucose and glycogen are broken down to meet energy needs, resulting in lactic acid as a…
Correct answer: Lactic acid238. Plant pigments responsible for red, yellow, and orange colors in many fruits and vegetables are:
- A. Chlorophyll a
- B. Chlorophyll b
- C. Carotenoids
- D. Cellulose
Explanation: The correct answer is Carotenoids. These pigments impart red, yellow, and orange hues to many fruits and vegetables.
Correct answer: Carotenoids239. The complete aerobic oxidation of glucose results in the synthesis of as many _ molecules of ATP.
- A. 16
- B. 26
- C. 36
- D. 46
Explanation: The complete aerobic oxidation of one molecule of glucose results in the synthesis of approximately 30-38 molecules of ATP.
Correct answer: 36- A. Energy
- B. Electrons
- C. Hydrogen protons
- D. All of the above
Explanation: Reduction is a chemical reaction in which a molecule gains electrons. This gain of electrons can be accompanied by the gain of hydrogen…
Correct answer: All of the above