The first stage is the light dependent reaction (it was called light reaction) and the chloroplast traps the light energy and transforms it into chemical energy which is ( NADPH) and (ATP), these are two molecules used in the second phase of photosynthesis. In the second step, this is called the light-independent reaction (it used to be called the dark reaction), NADPH provides the hydrogen atoms to help form glucose, and ATP provides the energy for the reactions used to make glucose. The phases are the literal meaning of photosynthesis, building with light. In the light-dependent reaction, photosynthesis depends on the energy flow initiated by light energy. Electrons are small particles that move in a specific orbit around the nuclei of atoms and have a small electrical charge. Light energy causes electrons in chlorophyll and other light-trapping pigments to surge upward and out of orbit; the electrons automatically return to their places, releasing energy, or vibrating energy, as they go, all in millionths of a second.