AP BIOLOGY

Detailed explanation-1: -In oxygenic photosynthesis, the first electron donor is water, creating oxygen (O2) as a by-product. In anoxygenic photosynthesis various electron donors are used.

Detailed explanation-2: -Oxygenic photosynthesis requires water, which acts as an electron donor molecule. The reactions which involve the trapping of sunlight are known as “light reactions", and result in the production of NADPH, adenosine triphosphate, and molecular oxygen.

Detailed explanation-3: -In green plant photosynthesis, water is the initial electron donor; NADPt is the final electron acceptor; and a proton gradient drives the electron flow from the donor to the acceptor: ATP light energy va proton ‘gradient manganese.

Detailed explanation-4: -In the light-dependent reactions, which take place at the thylakoid membrane, chlorophyll absorbs energy from sunlight and then converts it into chemical energy with the use of water. The light-dependent reactions release oxygen as a byproduct as water is broken apart.