Describe how Carbon Dioxide is assimilated in the Calvin cycle.

CO₂ from the atmosphere diffuses into the leaf through the stomata and then into the stroma within the chloroplasts of mesophyll cells.  In the stroma the enzyme Ribusco catalyes the combining of CO₂ with ribulose bisphosphate to form an intermediate which breaks down into two glycerate -3-phosphate molecules. The hydrolysis of ATP ( produced in the light dependent reaction) releases energy which is used to reduce glycerate -3 - phoshpate into triose phosphate. The reductant NADPH is oxidised to regenreate NAPD⁺ which is again able to accept hydrogen from the photolysis of water. Some triose phosphate molecules are used to produce useful organic substances like glucose while most are used to regenerate ribulose bisphosphate.