chlorofil

Chlorofil, more commonly called chlorophyll in English, refers to a family of green pigments that capture light energy for photosynthesis in plants, algae, and cyanobacteria. The most widespread forms are chlorophyll a and chlorophyll b, which reside in the thylakoid membranes of chloroplasts in plants and algae. Some groups also contain chlorophylls c, d or f, adapted to different light environments.

Chemistry and structure: Chlorophyll molecules are magnesium-containing porphyrin compounds with a long hydrophobic phytol tail that anchors them in membranes. The porphyrin ring system enables light absorption in the blue and red parts of the spectrum, while the tail helps organize the pigments within photosynthetic membranes. Chlorophyll a and b differ in the side chains attached to the ring, producing slightly different absorption characteristics.

Role in photosynthesis: Chlorophylls are the primary light-absorbing pigments that funnel excitation energy to reaction centers in photosystem II (P680) and photosystem I (P700). This energy transfer drives primary charge separation and electron transport, powering the synthesis of ATP and NADPH used to fix carbon dioxide into sugars. Oxygen evolution in algae and plants is a byproduct of this process.

Biosynthesis and distribution: Chlorophyll biosynthesis proceeds via a tetrapyrrole pathway that includes magnesium insertion into a porphyrin ring and attachment of a phytol tail. The pathway is tightly regulated and interconnected with other tetrapyrrole pigments such as heme.

Ecology and applications: Chlorophyll content reflects plant health and photosynthetic capacity; it is measured in agriculture and ecological studies using spectrometry or SPAD devices and remotes sensing.

History and naming: The term derives from Greek chloros "green" and phyllon "leaf" and the pigment was isolated in the early 19th century by Pelletier and Caventou.