Question

The first acceptor of electrons from an excited chlorophyll molecule of photosystem II is

• A. Quinone.
• B. Cytochrome.
• C. Iron-sulphur protein.
• D. Ferredoxin.

Answer 1

The correct option is A Quinone.

Light reaction of the photosynthesis starts from the excitation of chlorophyll by a photon. When a photon of light energy falls on chlorophyll molecule, it gets excited and moves on to a higher level called excited singlet state. The electron gap in the photosystem is further filled by the process of photolysis.

The extra pigments capture light energy and pass on the captured light energy to a specific chlorophyll a molecule called as reaction centre. The reaction centre of photosystem II is called P${}_{680}$, whereas reaction centre of photosystem I is called P${}_{700}$. In photosystem II the electrons emitted by reaction centre are first captured by pheophytin whereas in photosystem I, the electrons emitted by reaction centre are first captured by iron sulphur protein.

So, the correct answer is option A.