Flowers, corals, and even animal skin contain pigments which give them their colors. More important than their reflection of light is the ability of pigments to absorb certain wavelengths. In plants , algae, and cyanobacteria , pigments are the means by which the energy of sunlight is captured for photosynthesis. However, since each pigment reacts with only a narrow range of the spectrum, there is usually a need to produce several kinds of pigments, each of a different color, to capture more of the sun's energy. There are three basic classes of pigments.
Chlorophylls are greenish pigments which contain a porphyrin ring .
This is a stable ring-shaped molecule around which electrons are free to migrate. Because the electrons move freely, the ring has the potential to gain or lose electrons easily, and thus the potential to provide energized electrons to other molecules. This is the molecule which makes photosynthesis possible, by passing its energized electrons on to molecules which will manufacture sugars. The differences between the chlorophylls of these major groups was one of the first clues that they were not as closely related as previously thought. Carotenoids are usually red, orange, or yellow pigments, and include the familiar compound carotene, which gives carrots their color.