AP BIOLOGY

Detailed explanation-1: -The light-dependent reactions of photosynthesis take place within the thylakoids. These reactions occur when the pigment chlorophyll, located within the thylakoid membranes, captures energy from the sun (photons) to initiate the breakdown of water molecules.

Detailed explanation-2: -Light dependent reactions convert solar energy to chemical energy (in the form of ATP and NADPH). Sunlight and H2O are the reactant of the light dependent reaction. The sunlight is captured by photosystem II, and is used to excite electrons.

Detailed explanation-3: -Water is necessary for these reactions because it is split by an enzyme within the thylakoid membrane. This splitting of water releases electrons, hydrogen ions, and oxygen. The oxygen is released and the electrons are used to generate a proton-motive force.

Detailed explanation-4: -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.

Detailed explanation-5: -During oxygenic photosynthesis, light energy transfers electrons from water (H2O) taken up by plant roots to CO2 to produce carbohydrates. In this transfer, the CO2 is “reduced, ” or receives electrons, and the water is “oxidized, ” or loses electrons. Oxygen is produced along with carbohydrates.