AP BIOLOGY

Detailed explanation-1: -Chlorophyll is therefore said to “donate” an electron (Figure 5.12). To replace the electron in the chlorophyll, a molecule of water is split. This splitting releases an electron and results in the formation of oxygen (O2) and hydrogen ions (H+) in the thylakoid space.

Detailed explanation-2: -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.

Detailed explanation-3: -The light-dependent reactions begin in photosystem II. In PSII, energy from sunlight is used to split water, which releases two electrons, two hydrogen atoms, and one oxygen atom.

Detailed explanation-4: -Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose. The plant then releases the oxygen back into the air, and stores energy within the glucose molecules.

Detailed explanation-5: -The light reaction takes place in the thylakoid discs. There, water (H20) is oxidized, and oxygen (O2) is released. The electrons freed up from water are transfered to ATP and NADPH.