Question

explain the difference between substrate-level phosphorylation and oxidative phosphorylation. select the correct answer below: substrate-level phosphorylation is used only when there is no oxygen available to the cell. when there is oxygen available, oxidative phophorylation is used instead. substrate-level phosphorylation involves phosphorylation of atp to form adp, while oxidative phosphorylation converts adp to atp. substrate-level phosphorylation is an indirect process of atp production that occurs in other parts of the cell from the reactions that break down glucose. oxidative phosphorylation is the more direct production of atp during the breakdown of glucose by oxygen. substrate level phosphorylation occurs directly during certain steps of glucose breakdown, while oxidative phosphorylation is a more complicated process that occurs in other parts of the cell and uses an external electron acceptor.

Answer 1

Substrate-level phosphorylation is a direct ATP production process during glycolysis and the Krebs cycle, while oxidative phosphorylation is an indirect and more complex process involving the electron transport chain and occurs in mitochondria or plasma membranes, requiring oxygen.

Step-by-step explanation:

Difference Between Substrate-level Phosphorylation and Oxidative Phosphorylation

Substrate-level phosphorylation and oxidative phosphorylation are two methods of ATP production in cellular metabolism. Substrate-level phosphorylation is a direct process where a phosphate group is transferred from a substrate molecule to ADP to form ATP; this occurs during glycolysis and the Krebs cycle. On the other hand, oxidative phosphorylation is an indirect and more complex process, involving an electron transport chain and chemiosmosis. It occurs primarily in the mitochondria of eukaryotic cells and in the plasma membrane of prokaryotic cells. It is driven by a gradient formed by the transport of electrons, supplied by the molecules NADH and FADH2, through a series of carriers to the final electron acceptor, which is usually oxygen. This creates a proton gradient across the membrane, which is then used to generate ATP via the ATP synthase enzyme.

The statement that substrate-level phosphorylation is used only when there is no oxygen available is incorrect. It takes place both in the presence and absence of oxygen during certain steps of glucose breakdown. Oxidative phosphorylation involves converting ADP to ATP using the energy from the electron transport chain and does require oxygen in aerobic respiration. Therefore, unlike the idea that oxygen availability dictates the use of these paths, both substrate-level and oxidative phosphorylation can occur within the same cell, depending on the specific metabolic pathway in operation.