The final phase of cellular respiration in which the compounds NADH and FADH₂ are oxidized and their electrons pass along a chain of oxidation-reduction steps is called:
Correct answer: A. Electron transport chain
- A. Electron transport chain
- B. Glycolysis
- C. Kreb cycle
- D. Fermentation
Explanation
The electron transport chain is the correct answer because it is the final phase of cellular respiration where NADH and FADH₂ are oxidized, and their electrons pass through a series of redox reactions to generate a proton gradient that drives ATP synthesis. This process efficiently converts the energy stored in reduced coenzymes into usable cellular energy in the form of ATP, with oxygen acting as the terminal electron acceptor.Glycolysis breaks down glucose into pyruvate and produces NADH, but it is not the final phase of respiration.The Krebs cycle produces NADH and FADH₂ but does not oxidize them.Fermentation regenerates NAD⁺ anaerobically without using an electron transport chain.
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About Bioenergetics
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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