Plant Photosynthesis

PS I

Reaction centre: The reaction centre of PS I is P700

Cycling: PS I can go for cyclic photophosphorylation independently

Ratio: Chlorophyll: Carotenoid content is 20-30:1

Location of pigments: Pigments of PS I are located in non-apposed part of grana and stroma lamellae.

Source of electrons: It receives electrons from PS II during non-cyclic photophosphorylation.

Oxygen: Molecular oxygen is not evolved in this system.

Occurrence: It is involved both in cyclic and non-cyclic photophosphorylation.

PS II

Reaction centre: The reaction centre of PS II is P680

Cycling: PS II performs non-cyclic photophosphorylation in conjuncture with PS I.

Ratio: Chlorophyll: Carotenoid content is 3-7:1

Location of pigments: Pigments of PS II are found in apposed portion of grana lamellae.

Source of elements: It receives electrons due to photolysis of water.

Oxygen: PS II leads to photolysis of water and oxygen is evolved.

Occurrence: It is involved only in non-cyclic photophosphorylation.