AP BIOLOGY

Detailed explanation-1: -The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage molecule ATP and the reduced electron carrier NADPH. In plants, the light reactions take place in the thylakoid membranes of organelles called chloroplasts.

Detailed explanation-2: -In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ATP and NADPH. The energy that these molecules carry is stored in a bond that holds a single atom to the molecule. For ATP, it is a phosphate atom, and for NADPH, it is a hydrogen atom.

Detailed explanation-3: -During the process of photosynthesis, light penetrates the cell and passes into the chloroplast. The light energy is intercepted by chlorophyll molecules on the granal stacks. Some of the light energy is converted to chemical energy. During this process, a phosphate is added to a molecule to cause the formation of ATP.

Detailed explanation-4: -The production of ATP occurs through the process of photophosphorylation. When light energy hits the chlorophyll molecule, it is absorbed by photosystem I and photosystem II. This raises the energy levels of electrons within the photosystems, causing them to jump to higher energy levels.