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Multiple Choice
Which of the following best describes the electron transport chain in cellular respiration?
A
A process in the cytoplasm where glucose is broken down into pyruvate, producing ATP and NADH.
B
A cycle that converts acetyl-CoA into carbon dioxide and high-energy electron carriers.
C
A series of protein complexes in the inner mitochondrial membrane that transfer electrons and generate a proton gradient to produce ATP.
D
A pathway that synthesizes glucose from non-carbohydrate precursors.
Verified step by step guidance
1
Step 1: Begin by identifying the key components of cellular respiration. Cellular respiration consists of glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain (ETC). Each step has a distinct role in energy production.
Step 2: Focus on the electron transport chain (ETC). The ETC occurs in the inner mitochondrial membrane and involves a series of protein complexes that transfer electrons derived from NADH and FADH2.
Step 3: Understand the mechanism of the ETC. Electrons are passed through the protein complexes, and their energy is used to pump protons (H⁺) across the inner mitochondrial membrane, creating a proton gradient.
Step 4: Explain the role of the proton gradient. The proton gradient drives ATP synthesis through a process called chemiosmosis, where protons flow back into the mitochondrial matrix via ATP synthase, generating ATP.
Step 5: Compare the given options. The correct description of the electron transport chain is: 'A series of protein complexes in the inner mitochondrial membrane that transfer electrons and generate a proton gradient to produce ATP.' This matches the mechanism and location of the ETC in cellular respiration.