AP BIOLOGY

Detailed explanation-1: -Photosynthesis in plants and cyanobacteria produces both ATP and NADPH directly by a two-step process called noncyclic photophosphorylation. Because two photosystems-called photosystems I and II-are used in series to energize an electron, the electron can be transferred all the way from water to NADPH.

Detailed explanation-2: -This is accomplished by the use of two different photosystems in the light reactions of photosynthesis, one to generate ATP and the other to generate NADPH. Electrons are transferred sequentially between the two photosystems, with photosystem I acting to generate NADPH and photosystem II acting to generate ATP.

Detailed explanation-3: -Photosynthesis transforms light energy into chemical energy stored in glucose, and cellular respiration releases the energy from glucose to build ATP, which does the work of life.