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During which stage in the complete oxidation of glucose are the greatest number of ATP molecules formed from ADP -
A
Glycolysis
B
Krebs cycle
C
Electron transport chain
D
Conversion of pyruvic acid to acetyl CoA
Detailed Solution
Glycolysis gives a net gain of 2 ATP (by substrate level phosphorylation) per glucose, plus 2 NADH.
The conversion of 2 pyruvate to 2 acetyl CoA gives 2 NADH but no ATP directly.
The Krebs cycle (two turns per glucose) gives 2 ATP (GTP) directly, plus 6 NADH and 2 $FADH_2$.
All the NADH and $FADH_2$ are oxidised in the electron transport chain on the inner mitochondrial membrane. Each NADH gives about 3 ATP and each $FADH_2$ about 2 ATP by oxidative phosphorylation.
So out of the 36-38 ATP formed per glucose, about 32-34 ATP are formed in the electron transport chain.
So the greatest number of ATP molecules are formed during the electron transport chain.
The conversion of 2 pyruvate to 2 acetyl CoA gives 2 NADH but no ATP directly.
The Krebs cycle (two turns per glucose) gives 2 ATP (GTP) directly, plus 6 NADH and 2 $FADH_2$.
All the NADH and $FADH_2$ are oxidised in the electron transport chain on the inner mitochondrial membrane. Each NADH gives about 3 ATP and each $FADH_2$ about 2 ATP by oxidative phosphorylation.
So out of the 36-38 ATP formed per glucose, about 32-34 ATP are formed in the electron transport chain.
So the greatest number of ATP molecules are formed during the electron transport chain.