Cellular Respiration Glossary

A two-carbon molecule attached to coenzyme A, formed from pyruvate oxidation. It enters the Krebs cycle and is fully oxidized to CO2.

A membrane enzyme that uses the proton motive force to catalyze the synthesis of ATP from ADP and inorganic phosphate.

The process by which the flow of protons through ATP synthase, driven by a concentration gradient, produces ATP.

A series of protein complexes in the inner mitochondrial membrane that transfer electrons from NADH and FADH2 to oxygen, creating a proton gradient for ATP synthesis.

A coenzyme that acts as an electron carrier, similar to NAD+. FADH2 donates electrons to Complex II of the ETC, yielding fewer ATP than NADH.

An anaerobic process that regenerates NAD+ from NADH, allowing glycolysis to continue. Produces ethanol (alcoholic) or lactate (lactic acid) as byproducts.

The first stage of cellular respiration, occurring in the cytoplasm, that splits glucose into two pyruvate molecules with a net yield of 2 ATP and 2 NADH.

Also called the citric acid cycle; a series of reactions in the mitochondrial matrix that oxidizes acetyl-CoA to CO2, producing NADH, FADH2, and ATP.

A coenzyme that acts as an electron carrier. NAD+ is the oxidized form that accepts electrons; NADH is the reduced form that donates electrons to the ETC.

ATP production driven by the electron transport chain and chemiosmosis. It accounts for the vast majority of ATP generated during aerobic respiration.

The potential energy stored in the electrochemical gradient of protons across the inner mitochondrial membrane, used by ATP synthase to produce ATP.

A three-carbon molecule produced by glycolysis. In aerobic conditions it is converted to acetyl-CoA; in anaerobic conditions it is reduced to lactate or ethanol.

The direct transfer of a phosphate group from a substrate molecule to ADP to form ATP, without involving the electron transport chain.