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English: Photosynthesis is the process by which plants, some bacteria, and some protists use the energy from sunlight to produce sugar. The process of photosynthesis is divided into two main parts: the light dependent reactions and the light independent reactions (or the Calvin Cycle). During the process of photosynthesis, light is absorbed, ATP is generated, carbon dioxide is fixed and glucose is produced. Chlorophyll, located in the chloroplasts, absorbs waves of light. Once the light is captured, hydrogen electrons are pulled from water and the extra oxygen created by the splitting of water is released as a waste product. The electrons, after being accepted, then begin the process of generating ATP and are passed down an electron transport chain. While the electrons reduce each NADP+ to NADPH, a movement of protons across the concentration gradient generates the ATP. Finally, the ATP provides the energy required for glucose to be created from carbon dioxide and water. This final stage does not require light for it to commence but it often occurs when light is available.