MISA Biology Practice Exam

The stage of respiration that is characterized by yielding 36 ATP is the Electron Transport Chain. This final stage of aerobic respiration occurs in the inner mitochondrial membrane, where electron carriers NADH and FADH2, produced during earlier stages, donate electrons to the electron transport chain.

As electrons are passed along the chain through a series of protein complexes, they release energy, which is used to pump protons (H+) across the mitochondrial membrane into the intermembrane space, creating a proton gradient. This gradient drives protons back across the membrane through ATP synthase, a process known as chemiosmosis, leading to the synthesis of a substantial amount of ATP.

In total, when considering the entire process of aerobic respiration (which includes Glycolysis, the Krebs Cycle, and the Electron Transport Chain), up to 36 molecules of ATP can be produced from one molecule of glucose. This yield reflects the efficiency of the electron transport chain and its role in oxidative phosphorylation, making it the primary contributor to ATP generation in the cell.