What is the net ATP yield from glycolysis alone per molecule of glucose?

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Multiple Choice

What is the net ATP yield from glycolysis alone per molecule of glucose?

Explanation:
Glycolysis yields a small net energy payoff because you invest energy up front and then recoup more energy later in the pathway. You spend 2 ATP early to activate glucose, but later steps generate 4 ATP from two glyceraldehyde-3-phosphate molecules (1 ATP for each G3P in two payoff steps, plus 1 more ATP for each PEP-to-pyruvate conversion, totaling 4). Subtracting the 2 ATP invested gives a net gain of 2 ATP per glucose. Glycolysis also produces 2 NADH, which can be turned into more ATP if they’re shuttled into mitochondria, but that isn’t counted in glycolysis itself.

Glycolysis yields a small net energy payoff because you invest energy up front and then recoup more energy later in the pathway. You spend 2 ATP early to activate glucose, but later steps generate 4 ATP from two glyceraldehyde-3-phosphate molecules (1 ATP for each G3P in two payoff steps, plus 1 more ATP for each PEP-to-pyruvate conversion, totaling 4). Subtracting the 2 ATP invested gives a net gain of 2 ATP per glucose. Glycolysis also produces 2 NADH, which can be turned into more ATP if they’re shuttled into mitochondria, but that isn’t counted in glycolysis itself.

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