ATP Synthesis

Substrate-level phosphorylation: This is a type of ATP synthesis that occurs when an enzyme directly transfers a phosphate group from an organic molecule to ADP, creating ATP.

Oxidative phosphorylation: This is another method of ATP synthesis that happens within mitochondria. It uses energy released by electron transport chains to power the addition of a phosphate group to ADP, forming ATP.

Photophosphorylation: This form of ATP synthesis occurs in chloroplasts during photosynthesis. Light energy is used to add a phosphate group to ADP, producing ATP.