Final answer:
The Calvin cycle of photosynthesis occurs in the stroma of the chloroplast.
Step-by-step explanation:
The Calvin cycle of photosynthesis occurs in the stroma of the chloroplast.
Each chloroplast contains neat stacks called grana, which consist of sac-like membranes known as thylakoid membranes. The light reactions of photosynthesis occur in the thylakoid membranes, while the reactions of the Calvin cycle take place in the stroma.