chlorophylldependent

Chlorophylldependent is an adjective used in biology to describe organisms or biological processes that rely on chlorophyll pigments to capture light energy for photosynthesis. In chlorophylldependent photosynthesis, light absorbed by chlorophyll drives the light reactions, producing ATP and NADPH that power carbon fixation in the Calvin cycle. This mode of energy capture is characteristic of oxygenic photoautotrophs, including plants, green algae, and cyanobacteria, in which chlorophyll a is the dominant pigment and is often accompanied by chlorophyll b and other accessory pigments that extend light absorption.

Chlorophylldependent systems typically rely on chloroplasts in eukaryotes or homologous thylakoid membranes in cyanobacteria. The arrangement of photosystems I and II, electron transport chains, and pigment–protein complexes efficiently harvest light across available wavelengths and protect against photodamage.

The term also serves to distinguish chlorophylldependent photosynthesis from alternative pigment systems, such as bacteriochlorophyll-based photosynthesis in some anoxygenic bacteria, or from organisms that are nonphotosynthetic or rely on other energy sources. Evolutionarily, chloroplasts in plants and algae arose through endosymbiosis with cyanobacteria, which underpins chlorophylldependence in these lineages.