Question

Differentiate between PS-I and PS-II.

Answer 1

• PS-I is located on the outer surface of thylakoid membrane towards stroma whereas PS-II is located on the inner surface of the thylakoid membrane.
  

• PS-I is present in unstacked thylakoid membrane and causes light induced reduction of $NAD{P}^{+}$ whereas PS-II is predominantly present in stacked thylakoid membrane.
  
• PS-I is involved in both cyclic and non-cyclic photophosphorylation whereas PS-II is involved in non-cyclic photophosphorylation.
  
• In PS-I, molecular oxygen is not involved whereas in PS-II, molecular oxygen is evolved and photolysis of water takes place.
  
• In PS-I, reaction centre is made up of $P_{700}$, whereas in PS-lI, the reaction centre is made up of $P_{680}$