Within this organelle are disk-shaped structures called thylakoids that function as the site of photosynthesis. It is because embedded in the thylakoid membrane is the antenna complex consisting of proteins, and light-absorbing pigments, including chlorophyll (the green pigment) and carotenoids. The chlorophyll is capable of absorbing light energy for use in photosynthesis. The high amounts of chlorophyll give chloroplast a green color, making it easily recognizable from the other plastids.
Word origin: Greek words chloros which means green and plast which means form or entity.