Question

Write any six differences between cyclic and non-cyclic photophosphorylation.

Answer 1

The process of photosynthesis is completed in two main steps-light reaction and dark reaction. The light reaction is the light-dependent reaction where the assimilatory powers are generated in the grana of the chloroplast.

Complete answer:
In this question, we will be dealing with the key differences between cyclic and non-cyclic photophosphorylation. Using a table lets list the key differences between them,

Cyclic photophosphorylation	Non-cyclic photophosphorylation
In this, the electrons move in a circular pattern.	The electron movement is non-cyclic.
It involves only photosystem I (PS I)	It involves both photosystems I and II (PS I and PS II)
Photolysis of water does not occur.	Photolysis of water occurs.
P700 is the electron donor and the final electron acceptor.	P680 is the first electron donor and NADP+ is the final electron acceptor.
Oxygen is not evolved.	Oxygen is evolved.
Cyclic photophosphorylation usually occurs at a low light intensity.	Non-cyclic photophosphorylation is favoured by high light intensity.
Photolysis of water does not take place	Photolysis of water takes place
Only ATP is synthesised	Both ATP and reduced coenzymes are synthesised
It generally occurs at low light density	It generally occurs at high light intensity

Note: It is to be noted that both cyclic and non-cyclic photophosphorylation are light-dependent reactions and produce ATP. The other similarities are,
i) They are both electron transport systems.
ii) In both the cycles, ATP is produced.
iii)They both are involved in production of assimilatory powers.
iv) They are both dependent on light.