NADP: a molecule that plays an important part in the transport of electrons. In the light-dependent reaction of photosynthesis, light is absorbed by chlorophyll molecules. This causes some of the electrons in the chlorophyll to become excited. They are picked up by NADP, which is converted to reduced NADP in the process. This reduced NADP plays an important part in the conversion of carbon dioxide to carbohydrate in the light-independent reaction.