Light Independent Stage

• the light independent stage takes place in the stroma of the chloroplast and is dependent on the products (ATP & NADPH) from the light dependent stage
• during this stage, inorganic carbon dioxide 

  is ‘fixed’ into organic compounds
• this stage is known as the Calvin cycle
• 1. carbon dioxide (1C) combines with the (5C) compound ribulose biphosphate (RuBP),catalysed by the enzyme ribulose biphosphate carboxylase, forming two molecules of (3C) glycerine phosphate
• 2. ATP and NADPH are used to reduce the glycerate phosphate into triose phosphate, the NADPH provides the H- ions required and the ATP provides the energy
• 3. 5/6 molecules of triose phosphate produced are used in the recycling of ribulose biphosphate (5C), ATP is used to provide the phosphate and energy required to make RuBP
• 4. 1/6 of the triose phosphate made in the light independent reaction is used to produce other organic molecules such as glucose, sucrose, starch, glycerol, fatty acid and amino acids
• 5. direct light is not required for this stage but it will only take place when light is present as it relies on the products produced in the light dependent stage
• The Calvin cycle produces one molecule of glucose per turn of the cycle