AP BIOLOGY

Detailed explanation-1: -Answer and Explanation: During electron transport through the electron transport system, protons (H+) get pumped from the matrix to the intermembrane space.

Detailed explanation-2: -The electrons flow through the electron transport chain, causing protons to be pumped from the matrix to the intermembrane space.

Detailed explanation-3: -Protons are pumped out of the matrix at complexes I, III and IV (2 per complex). The resulting proton gradient is used to drive ATP synthesis: 2 H+ per ATP produced. The proton gradient also creates a charge difference across the inner mitochon.

Detailed explanation-4: -Complex I feeds electrons from the soluble carrier molecule NADH into the respiratory chain and transfers them to a quinol in the membrane. The energy released in the electron transfer reaction is utilized for pumping four protons from the matrix into the crista lumen.

Detailed explanation-5: -In cell respiration, the proton pump uses energy to transport protons from the matrix of the mitochondrion to the inter-membrane space. It is an active pump that generates a proton concentration gradient across the inner mitochondrial membrane because there are more protons outside the matrix than inside.