AP BIOLOGY

Detailed explanation-1: -Fate of pyruvate: The fate of pyruvate depends on the availability of oxygen. If oxygen is available: If oxygen is available, pyruvate is transported to mitochondria. Inside the mitochondria, pyruvate undergoes oxidative decarboxylation and produces acetyl CoA.

Detailed explanation-2: -When oxygen is not present or if an organism is not able to undergo aerobic respiration, pyruvate will undergo a process called fermentation. Fermentation does not require oxygen and is therefore anaerobic. Fermentation will replenish NAD+ from the NADH + H+ produced in glycolysis.

Detailed explanation-3: -Lactic acid fermentation: Pyruvate reacts with the Lactate dehydrogenase enzyme to produce Lactic Acid and molecules of ATP. Alcoholic fermentation: Pyruvate is converted to Acetaldehyde and Acetaldehyde into Ethanol along with a mole of carbon dioxide gas-producing molecules of ATP.

Detailed explanation-4: -In the absence of oxygen, pyruvate is converted to lactate, and NADH is reoxidized to NAD+. In the presence of oxygen, pyruvate is converted to acetyl-CoA and then enters the citric acid cycle. More ATP can be formed from the breakdown of glucose when oxygen is present.

Detailed explanation-5: -In the presence of oxygen, pyruvate is transformed into an acetyl group attached to a carrier molecule of coenzyme A. The resulting acetyl CoA can enter several pathways, but most often, the acetyl group is delivered to the citric acid cycle for further catabolism.