Which reducing equivalent is produced in glycolysis and can yield additional ATP in mitochondria?

Which reducing equivalent is produced in glycolysis and can yield additional ATP in mitochondria?

• A. FADH2
• B. NAD+
• C. NADH
• D. ATP

Answer: (C)

Glycolysis produces a reducing equivalent in the form of NADH when glyceraldehyde-3-phosphate is oxidized, making NADH the carrier of high-energy electrons generated in this pathway. That NADH can feed electrons into the mitochondrial electron transport chain, and through oxidative phosphorylation it yields additional ATP beyond the ATP made directly in glycolysis. Since this NADH is produced in the cytosol, the electrons must be shuttled into the mitochondria by transfer systems, and the amount of ATP gained depends on which shuttle is used. NAD+ is the oxidized form, not the reduced carrier produced here, so it isn’t the reducing equivalent generated. FADH2 is another reducing equivalent but is typically produced in different steps (mainly in the mitochondria), and ATP is energy produced, not a reducing carrier.

Glycolysis produces a reducing equivalent in the form of NADH when glyceraldehyde-3-phosphate is oxidized, making NADH the carrier of high-energy electrons generated in this pathway. That NADH can feed electrons into the mitochondrial electron transport chain, and through oxidative phosphorylation it yields additional ATP beyond the ATP made directly in glycolysis. Since this NADH is produced in the cytosol, the electrons must be shuttled into the mitochondria by transfer systems, and the amount of ATP gained depends on which shuttle is used. NAD+ is the oxidized form, not the reduced carrier produced here, so it isn’t the reducing equivalent generated. FADH2 is another reducing equivalent but is typically produced in different steps (mainly in the mitochondria), and ATP is energy produced, not a reducing carrier.