AP BIOLOGY

Detailed explanation-1: -Glycolysis, which is the first step in all types of cellular respiration is anaerobic and does not require oxygen. If oxygen is present, the pathway will continue on to the Krebs cycle and oxidative phosphorylation.

Detailed explanation-2: -The first stage of cellular respiration, called glycolysis, takes place in the cytoplasm. In this step, enzymes split a molecule of glucose into two molecules of pyruvate, which releases energy that is transferred to ATP.

Detailed explanation-3: -There are three main steps of cellular respiration: glycolysis; the citric acid (TCA) or the Krebs cycle; and the electron transport chain, where oxidative phosphorylation occurs. The TCA cycle and oxidative phosphorylation require oxygen, while glycolysis can occur in anaerobic conditions.

Detailed explanation-4: -Answer and Explanation: The electron transport chain is the stage of cellular respiration which requires the oxygen that we breathe.