Question

What is water’s role in the light reaction of photosynthesis?

Answer 1

The correct answer is - Its electrons are used to form NADPH.

On receiving light energy, electrons are expelled from the reaction center of photosystem II. The expelled electrons finally reduces oxidized NADH⁺ to NADH. The oxidized reaction center of photosystem II split water into protons, electrons and oxygen. The electrons released from water reduces oxidized reaction center of photosystem II. Thus, oxidized reaction center of photosystem II gets back its expelled electrons. Therefore, electrons from water forms NADH.

Answer 2

The correct answer is option A, Its electrons are used to form glucose.

Reason -

In the light reaction phase of photosynthesis, the water gets broken into its constituent’s elements that are oxygen, H+ ions and free electrons. This process takes place in the thylakoid membrane in the presence of an enzyme. The released free electrons replace the loss of electron during the process light dependent reaction in the photosystem II.