1. Photosynthesis
The Calvin Cycle

2. The Calvin Cycle The purpose of the Calvin cycle is to create G3P
G3P is a 3-carbon organic compound that can be turned into glucose, amino acids, and lipids

3. The Calvin Cycle
The Calvin cycle occurs in the stroma of the chloroplast
It uses the ATP and NADPH created during the light-dependent reactions for energy
Unlike the LDR, the Calvin cycle can occur all the time, as long as there is sufficient energy from the LDR

4. The Calvin Cycle
The main function of the Calvin cycle is to “fix” carbon in the leaf
Since carbon dioxide is a gas, it must be turned into a solid that cannot escape through the stomata

5. The Calvin Cycle 1. CO2 enters through the stoma
2. CO2 combines with a compound called RuBP that must always be present in the stroma of the chloroplast
The enzyme RUBISCO is responsible for this reaction.

6. The Calvin Cycle
3. The compound formed when RuBP and CO2 combine splits into two molecules of PGA.
4. PGA is turned into G3P
This requires the expenditure of ATP and NADPH

7. The Calvin Cycle
5. For every twelve molecules of G3P produced, two are used to make food

8. The Calvin Cycle
6. The other ten molecules of G3P are used to regenerate the RuBP that the stroma needs for the Calvin cycle to continue.
This requires the additional expenditure of ATP for energy