chlorofilu

Chlorofilu, commonly known as chlorophyll, is a group of green pigments that capture light energy for photosynthesis. In higher plants and many algae the two main forms are chlorophyll a and chlorophyll b, while some algae and bacteria also contain chlorophyll c, d, or e. These pigments are essential for converting light energy into chemical energy.

Chemically, chlorophylls are magnesium-containing porphyrin compounds with long hydrophobic phytol side chains that anchor them in the thylakoid membranes of chloroplasts. The conjugated ring system and the central magnesium ion determine their light absorption properties, giving them a green appearance by reflecting green light and absorbing blue and red wavelengths.

Chlorophylls play a central role in photosynthesis. Chlorophyll a is the primary pigment in the reaction centers of photosystems I and II, directly participating in the electron transport chain. Chlorophyll b acts as an accessory pigment, expanding the spectrum of usable light by transferring absorbed energy to chlorophyll a.

Biosynthesis and metabolism: Chlorophylls are produced through a multistep pathway beginning with 5-aminolevulinic acid, proceeding to protoporphyrin IX, then insertion of Mg2+ by Mg-chelatase, and subsequent formation of chlorophyllide and its esterification with phytol. In green plants, light-dependent steps convert protochlorophyllide to chlorophyllide, enabling chlorophyll formation during greening.

Occurrence and turnover: Chlorophylls are widespread in plants, algae, cyanobacteria, and some bacteria. They degrade during senescence or stress, yielding pheophytin and various nonfluorescent chlorophyll catabolites, contributing to autumn leaf color changes. Chlorophylls are also used as natural colorants in the food industry (E140).