AP BIOLOGY

Detailed explanation-1: -The ATP and NADPH from the light-dependent reactions are used to make sugars in the next stage of photosynthesis, the Calvin cycle. In another form of the light reactions, called cyclic photophosphorylation, electrons follow a different, circular path and only ATP (no NADPH) is produced.

Detailed explanation-2: -The light-dependent reactions convert light energy into chemical energy. The goal of the light-dependent reactions of photosynthesis is to collect energy from the sun and break down water molecules to produce ATP and NADPH. These two energy-storing molecules are then used in the light-independent reactions.

Detailed explanation-3: -reactions (how do the light-independent reactions rely on the light reactions?) The light-independent reactions require energy to fix carbon. This energy is supplied by ATP and NADPH, which are formed during the E.T.C. of the light-dependent reactions.

Detailed explanation-4: -In the light-dependent reactions, energy from sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy. In the light-independent reactions, the chemical energy harvested during the light-dependent reactions drive the assembly of sugar molecules from carbon dioxide.

Detailed explanation-5: -ATP and NADPH are used to convert the six molecules of 3-PGA into six molecules of a chemical called glyceraldehyde 3-phosphate (G3P). That is a reduction reaction because it involves the gain of electrons by 3-PGA. Recall that reduction is the gain of an electron by an atom or molecule.