Phosphorylation
Definition of Phosphorylation:
Formation of a phosphate derivative of a biomolecule, usually by enzymatic transfer of a phosphate group from ATP
Types of Phosphorylation:
1) Photophosphorylation or photosynthetic phosphorylation.
a) Cyclic photophosphorylation
b) Noncyclic photophosphorylation
2) Substrate level photophosphorylation.
3) Oxidative phosphorylation.
A) Photophosphorylation: The enzymatic formation of ATP from ADP coupled to the light dependent transfer of electrons in photosynthetic cells.
a) Cyclic photophosphorylation – ATP synthesis driven by cyclic electron flow through photosystem I.
b) Non cyclic photophosphorylation – The expelled electrons do not return to the chlorophyll.
B) Substrate Level Phosphorylation: Phosphorylated substrates donate inorganic phosphate to produce ATP (Non oxidative)
C) Oxidative phosphorylation: (linked to electron transport). The enzymatic phosphorylation of ADP to A TP coupled to electron transfer, from a substrate to molecular oxygen.