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: -Atmospheric carbon dioxide is converted to glucose during the Calvin-Benson cycle. This requires the overall reduction of CO2, using the electrons available from the oxidation of NADPH. Thus the dark reactions represent a redox pathway. NADPH is oxidized to NADP+ and CO2 is reduced to glucose.

Detailed explanation-3: -ATP and NADPH use their stored energy to convert the three-carbon compound, 3-PGA, into another three-carbon compound called G3P. This type of reaction is called a reduction reaction, because it involves the gain of electrons.

Detailed explanation-4: -The light-dependent reactions convert light energy into chemical energy, producing ATP and NADPH. The light-independent reactions use the ATP and NADPH from the light-dependent reactions to reduce carbon dioxide and convert the energy to the chemical bond energy in carbohydrates such as glucose.