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Multiple Choice
Which step of cellular respiration yields the most ATP?
A
Glycolysis
B
Citric acid cycle (Krebs cycle)
C
Electron transport chain and oxidative phosphorylation
D
Fermentation
Verified step by step guidance
1
Step 1: Understand the process of cellular respiration, which consists of three main stages: glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain coupled with oxidative phosphorylation.
Step 2: Recall that glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate, yielding a small amount of ATP (net gain of 2 ATP per glucose molecule).
Step 3: Learn that the citric acid cycle (Krebs cycle) occurs in the mitochondrial matrix and generates electron carriers (NADH and FADH2) while producing a small amount of ATP (2 ATP per glucose molecule).
Step 4: Understand that the electron transport chain and oxidative phosphorylation occur in the inner mitochondrial membrane, where electrons from NADH and FADH2 are transferred through protein complexes, creating a proton gradient that drives ATP synthesis via ATP synthase. This step yields the most ATP (approximately 28-34 ATP per glucose molecule).
Step 5: Compare the ATP yield of each stage and recognize that the electron transport chain and oxidative phosphorylation are the most efficient steps in terms of ATP production during cellular respiration.