Question

A glucose molecule is completely broken down upon completion of glycolysis and the citric acid cycle. However, these two processes yield only a few ATPs. Where is the rest of the energy that the cell can obtain from the glucose molecule?

a in NADH and FADH2
b lost as heat
c in the oxygen used in the electron transport chain
d in FAD and NAD+

Answer 1

The rest of the energy from a glucose molecule is found in NADH and FADH2, which are used in the electron transport chain (ETC) to produce ATP.

Step-by-step explanation:

The rest of the energy that the cell can obtain from a glucose molecule is found in NADH and FADH2. Glycolysis and the citric acid cycle produce a small amount of ATP, but the majority of the energy is stored in NADH and FADH2. These molecules carry high-energy electrons that are used in the electron transport chain (ETC) to produce more ATP.

The ETC is the final stage of cellular respiration, where NADH and FADH2 donate their electrons. As the electrons pass through protein complexes in the ETC, they generate energy that is used to pump hydrogen ions across the membrane. The flow of these hydrogen ions back into the mitochondria through ATP synthase generates ATP, which is the cell's main energy source.

In summary, while glycolysis and the citric acid cycle produce some ATP, the majority of the energy from a glucose molecule is obtained through the electron transport chain using NADH and FADH2.