What is Phosphorylation?

Phosphorylation    The reaction that involves the addition of a phosphate group (Pi) to a molecule is phosphorylation. There are two kinds of phosphorylation: 1. Substrate Phosphorylation    Phosphate from one molecule (substrate) is transferred to another molecule: E X-P + ADP ® X + ATP 2. Oxidative Phosphorylation    Involves the energy released when compounds (NADH + FADH2) release their electrons (are oxidized) and the electrons are transferred along an electron transport chain. The electrons are finally given to oxygen (final oxidation). ATP results from chemiosmotic coupling which captures the energy that is released as the electrons are transported and uses it to synthesize ATP by means of ATP synthase: ATP-synthase ADP + Pi ® ATP