Which part of the chloroplast contains chlorophyll?

Chlorophyll is the pigment responsible for capturing light energy during the process of photosynthesis, and it is primarily located in the thylakoid membranes of the chloroplast. The thylakoids are flattened, disk-like structures stacked in groups known as grana, and they contain the chlorophyll molecules that absorb light, particularly in the blue and red wavelengths.

This absorption of light energy is essential for driving the light-dependent reactions of photosynthesis, where energy from sunlight is converted into chemical energy in the form of ATP and NADPH. The stroma, while it plays a critical role in the next stage of photosynthesis (the Calvin cycle), does not contain chlorophyll. The outer and inner membranes of the chloroplast serve structural and protective functions but do not involve the pigment required for light absorption. Thus, the thylakoid membranes are correctly identified as the location of chlorophyll.