AP BIOLOGY

Detailed explanation-1: -In the presence of oxygen, the next stage after glycolysis is oxidative phosphorylation, which feeds pyruvate to the Krebs Cycle and feeds the hydrogen released from glycolysis to the electron transport chain to produce more ATP (up to 38 molecules of ATP are produced in this process).

Detailed explanation-2: -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. However, if oxygen is not present, some organisms can undergo fermentation to continually produce ATP.

Detailed explanation-3: -Results of Glycolysis The energy to split glucose is provided by two molecules of ATP. As glycolysis proceeds, energy is released, and the energy is used to make four molecules of ATP. As a result, there is a net gain of two ATP molecules during glycolysis.

Detailed explanation-4: -In the presence of oxygen organisms are capable of using the Kreb’s Cycle. The reason oxygen is required is because the NADH and [FADH2] produced in the Kreb’s Cycle are able to be oxydized in the electron transport chain (ETC) thus replenishing the supply of NAD+ and [FAD].