The light-independent reactions of photosynthesis take place within the stroma. It contains enzymes that work with ATP and NADPH to “fix” carbon from carbon dioxide into molecules that can be used to build glucose. The chloroplast’s own genetic material (separate from that of the cell) is also stored in the stroma.
The interior of the chloroplast contains another membrane—the thylakoid membrane—which is folded to form numerous connected stacks of discs. Each disc is a thylakoid and each stack is a granum (pl. grana).
The light-dependent reactions of photosynthesis take place within the thylakoids. These reactions occur when the pigment chlorophyll, located within the thylakoid membranes, captures energy from the sun (photons) to initiate the breakdown of water molecules.
