AP Biology/Photosynthesis


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Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into energy (sugar). The chemical reaction is:

It is because of this process that plants are defined as autotrophs; they make their own food, as opposed to heterotrophs which consume each other and the autotrophs for food. The photosynthetic process itself has two main parts: the light-dependent reactions in which the energy of sunlight is used to load energy into the energy transfer molecule common to all life forms: Adenosine Triphosphate or ATP and to load the high energy electron carrier abbreviated NADPH with high energy electrons. The energy needed to power these steps is collected by chlorophyll molecules found arranged into photosystems in the chloroplasts.