Photosynthesis The 2 reactions
Equation
2 Reactions Light-dependent Light-independent Aka “dark reaction” or “Calvin Cycle”
Light Dependent Where do they happen? What goes in and out? Occur in the grana of the chloroplast What goes in and out? Water comes in Oxygen goes out What happens? Photosynthesis begins when pigments (chlorophyll) traps light energy This light energy pulls electrons from water molecules causing the water to split releasing O2
Light Independent Where do they happen? What goes in and out? Occur in the stroma of the chloroplast What goes in and out? Carbon Dioxide goes in Glucose goes out What happens? Six carbon atoms from carbon dioxide are fixed to produce one molecule of glucose (C6H12O6) These reactions are sometimes called “dark reactions’ because they do not require light
Working together The two sets of photosynthetic reactions work together within the plant The light dependent reactions trap sunlight energy in chemical form The light independent reactions use that chemical energy to produce stable, high-energy sugars from carbon dioxide and water