Step 1: CO2 diffuses into the stroma from surrounding cytosol. An enzyme combines each CO2 molecule with a five-carbon
molecule called ribulose bisphosphate(RuBP). The six-carbon molecules that result are very unstable, and they each immediately
split into two three-carbon molecules. These three-carbon molecules are called 3-phosphoglycerate(3-PGA)
Step 2: Each molecule of 3-PGA is converted into another three-carbon molecule,G3P, in a two part process.
Step 3: One of the G3P molecules leaves the Calvin Cycle and is used to make organic compounds (carbohydrates)
in which energy is stored for later use.
Step 4: The remaining G3P molecules are converted back into RuBP throught the addition of phosphate groups
from ATP molecules. The resulting RuBP molecules then enter the Calvin Cycle again.