AP BIOLOGY

Detailed explanation-1: -The TCA cycle begins with an enzymatic aldol addition reaction of acetyl CoA to oxaloacetate, forming citrate. The citrate is isomerized by a dehydration-hydration sequence to yield (2R, 3S)-isocitrate. Further enzymatic oxidation and decarboxylation gives 2-ketoglutarate.

Detailed explanation-2: -Krebs cycle or TCA cycle takes place in the matrix of mitochondria under aerobic condition. Step 1: The first step is the condensation of acetyl CoA with 4-carbon compound oxaloacetate to form 6C citrate, coenzyme A is released. The reaction is catalysed by citrate synthase.

Detailed explanation-3: -The citric acid cycle begins with the transfer of a two-carbon acetyl group from acetyl-CoA to the four-carbon acceptor compound (oxaloacetate) to form a six-carbon compound (citrate). The citrate then goes through a series of chemical transformations, losing two carboxyl groups as CO2.

Detailed explanation-4: -Figure 7.10. 1: The citric acid cycle: In the citric acid cycle, the acetyl group from acetyl CoA is attached to a four-carbon oxaloacetate molecule to form a six-carbon citrate molecule. Through a series of steps, citrate is oxidized, releasing two carbon dioxide molecules for each acetyl group fed into the cycle.