Which molecule acts as an electron carrier that is reduced to NADH during cellular respiration?

Which molecule acts as an electron carrier that is reduced to NADH during cellular respiration?

• A. NAD+
• B. NADP+
• C. FAD
• D. ATP

Answer: (A)

Electron carriers in cellular respiration accept and deliver electrons to power ATP production. NAD+ acts as one such carrier in its oxidized form, ready to accept electrons and a proton to become NADH. This NADH carries the captured energy to the mitochondrial electron transport chain, where its electrons help pump protons across the membrane and ultimately drive ATP synthesis. NAD+ also functions in glycolysis and the citric acid cycle, getting reduced at several steps to NADH. In contrast, NADP+ is mainly used to produce NADPH in photosynthesis and biosynthetic pathways, FAD is another carrier that becomes FADH2 but does not form NADH, and ATP is the energy currency, not an electron carrier.

Electron carriers in cellular respiration accept and deliver electrons to power ATP production. NAD+ acts as one such carrier in its oxidized form, ready to accept electrons and a proton to become NADH. This NADH carries the captured energy to the mitochondrial electron transport chain, where its electrons help pump protons across the membrane and ultimately drive ATP synthesis. NAD+ also functions in glycolysis and the citric acid cycle, getting reduced at several steps to NADH. In contrast, NADP+ is mainly used to produce NADPH in photosynthesis and biosynthetic pathways, FAD is another carrier that becomes FADH2 but does not form NADH, and ATP is the energy currency, not an electron carrier.