Question

How many components listed below are part of cyclic ETS?
P${}_{700}$, P${}_{680}$, NADP reductase, hydrogen carrier, PS I, Water Splitting Complex, PS II

• A. Two
• B. Three
• C. Five
• D. Four

Answer 1

Answer: (A)

Two

Cyclic ETS comprises of photosystem I i.e. PS I. The photocentre of PS I is a special chlorophyll-a molecule which is called P${}_{700}$. Non-cyclic ETS comprises of both photosystem I and photosystem II. The photocentre of PS II is chlorophyll-a which is called P${}_{680}$. It also consists of water splitting complex in which photolysis of water takes place.

Hence, PS I and P${}_{700}$ are components of cyclic ETS. So, the correct answer is 'Two'.