AP BIOLOGY

Detailed explanation-1: -First, acetyl CoA combines with oxaloacetate, a four-carbon molecule, losing the CoA group and forming the six-carbon molecule citrate. After citrate undergoes a rearrangement step, it undergoes an oxidation reaction, transferring electrons to NAD+ to form NADH and releasing a molecule of carbon dioxide.

Detailed explanation-2: -In the citric acid cycle, the two carbons that were originally the acetyl group of acetyl CoA are released as carbon dioxide, one of the major products of cellular respiration, through a series of enzymatic reactions.

Detailed explanation-3: -The citric acid cycle is a series of reactions that produces two carbon dioxide molecules, one GTP/ATP, and reduced forms of NADH and FADH2.

Detailed explanation-4: -In step two, an enzyme called aconitase converts citrate into isocitrate. Next, an isocitrate dehydrogenase enzyme oxidizes isocitrate, a six-carbon molecule, to a five-carbon -ketoglutarate. The carbon that was lost is released as carbon dioxide and one NADH is also formed.

Detailed explanation-5: -Decarboxylation takes place twice in the TCA cycle forming two carbon dioxide molecules. Since two cycles are required thus, 2 CO2 molecules are released per cycle and in total 4 carbon dioxide molecules are released for one molecule of glucose in the TCA cycle.