Photosynthetic Pigments

Synonyms

Pigment molecules

Definition

Photosynthetic pigments are the molecules responsible for absorbing electromagnetic radiation, for transferring the energy of the absorbed photons to the reaction center, and for photochemical conversion in the photosynthetic systems of organisms capable of photosynthesis.

Overview

Photosynthetic pigments derive their name from the fact they can absorb visible light (from Lat. pi(n)g(ere) – to paint + ment(um)). The molecules of photosynthetic pigments are quite ubiquitous and are always composed of chlorophylls and carotenoids. Chlorophylls consist of a porphyrin ring, which is bounded to an ion Mg²⁺, attached to a phytol chain. Chlorophylls form part of reaction centers – where the photochemical conversion takes place – and antennas, or light-harvesting complexes, i.e., collectors of electromagnetic radiation, whereas carotenoids are found only in the antennas. Both types of molecules are found in “quasi-crystalline” structures in photosynthetic...