Biology · Bioenergetics

Glycolysis is the first stage of cellular respiration that occurs in the cytoplasm and can happen with or without oxygen. It breaks one glucose molecule into two pyruvate molecules, producing a small amount of ATP and NADH.

Glycolysis is the cellular process that can take place both in the presence and absence of oxygen. Glycolysis is the initial stage of cellular respiration, and it occurs in the cytoplasm of the cell. This process involves the breakdown of one molecule of glucose into two molecules of pyruvate, along with the production of a small amount of adenosine triphosphate (ATP) and reduced electron carriers (such as NADH).

Pyruvic acid oxidation is a crucial step in cellular respiration, as the term uses the word oxidation, which means that, for further processing, oxygen is required, and this step occurs inside the mitochondria by decarboxylation

Krebs cycle starts when acetyl-CoA combines with oxaloacetate to form citrate. The cycle does not directly use oxygen, but it needs oxygen indirectly.

This is because oxygen is required in the electron transport chain to make NAD⁺ and FAD available again.

Without oxygen, the Krebs cycle stops as these molecules cannot be regenerated.

Oxygen is the ultimate electron acceptor in this reaction that results in ATP formation. Both ATP and chemiosmosis would cease without the presence of Oxygen