Question

What most directly provides the energy necessary to synthesize ATP during oxidative phosphorylation?

1) Glycolysis
2) Krebs cycle
3) Electron transport chain
4) Photosynthesis

Answer 1

The electron transport chain most directly provides the energy necessary for ATP synthesis during oxidative phosphorylation. It creates a proton gradient that drives the production of ATP through chemiosmosis, a mechanism more efficient than substrate-level phosphorylation.

Step-by-step explanation:

The energy necessary to synthesize ATP during oxidative phosphorylation is most directly provided by the electron transport chain. During the catabolism of glucose, glycolysis produces pyruvate which is then converted into acetyl-CoA for use in the citric acid cycle (also known as the Kreb's cycle). This cycle generates NADH and FADH2, which are electron carriers that donate electrons to the electron transport chain. As electrons move through the chain, a proton gradient is established across the mitochondrial membrane leading to the production of ATP through a process known as chemiosmosis.

Oxidative phosphorylation includes two key processes: the electron transport and chemiosmosis. It is far more efficient at generating ATP compared to substrate-level phosphorylation which occurs in glycolysis and the citric acid cycle.