Chlorophyll is the pigment that gives plants and algae their green color. Plants use chlorophyll to trap light needed for photosynthesis.

The basic structure of chlorophyll is a porphyrin ring similar to that of heme in hemogloboin, although the central atom in chlorophyll is magnesium instead of iron. The long hydrocarbon (phytol) tail attached to the porphyrin ring makes chlorophyll fat-soluble and insoluble in water.

Two different types of chlorophyll (chlorophyll a and chlorophyll b) are found in plants. The small difference is one of the side chains allows each type of chlorophyll to absorb light at slightly different wavelengths.