The light reactions take place in the structures of the chloroplast called the

In photosynthesis, the light-dependent reaction takes place on the thylakoid membranes. The inside of the thylakoid membrane is called the lumen, and outside the thylakoid membrane is the stroma, where the light-independent reactions take place.

The "light-independent" or dark reactions happen in the stroma of the chloroplasts. This is also known as the Calvin Cycle.