AP BIOLOGY

Detailed explanation-1: -Krebs cycle is an anaerobic process.

Detailed explanation-2: -Thus, if oxygen is not present, the respiratory cycle cannot function, which shuts down the Krebs cycle. For this reason, the Krebs cycle is considered an aerobic pathway for energy production.

Detailed explanation-3: -The tricarboxylic acid (TCA) cycle, also known as the Krebs or citric acid cycle, is the main source of energy for cells and an important part of aerobic respiration.

Detailed explanation-4: -Hence the correct answer is the option ‘The cycle starts with condensation of an acetyl group (acetyl CoA) with pyruvic acid to yield citric acid’.

Detailed explanation-5: -Glycolysis – It is an anaerobic process, which occurs in the cytoplasm of the cell. In glycolysis, partial oxidation of glucose occurs, which yields two molecules of pyruvic acid. Krebs Cycle – It is an aerobic process that takes place in the mitochondria of the cell.