AP BIOLOGY

Detailed explanation-1: -Thus the dark reactions represent a redox pathway. NADPH is oxidized to NADP+ and CO2 is reduced to glucose.

Detailed explanation-2: -Dark reaction is a light-independent process in which sugar molecules are formed from carbon dioxide and water molecules. This reaction occurs in the stroma of the chloroplast where it utilizes the products of the light reaction. Since this is not directly dependent on light, it is called as the dark reaction.

Detailed explanation-3: -During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. 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.

Detailed explanation-4: -Photosynthesis occurs in two phases-light reaction and dark reaction. During light reaction water undergoes photolysis releasing oxygen and reduced NADPH2 and ATP molecules are synthesized. During the dark reaction, NADPH2 and ATP are used to reduce carbon dioxide into sugars.

Detailed explanation-5: -Thus, whole-chain photosynthetic electron transport uses the energy of sunlight to oxidize low energy water, and reduce high-energy NADPH.