Chlorophyll a Chlorophyll a Chlorophyll "a" is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light. It also reflects green-yellow light, and as such contributes to the observed green color of most plants. This photosynthetic pigment is essential for photosynthesis in eukaryotes, cyanobacteria and prochlorophytes because of its role as primary electron donor in the electron transport chain. Chlorophyll "a" also transfers resonance energy in the antenna complex, ending in the reaction center where specific chlorophylls P680 and P700 are located. Chlorophyll "a" is essential for most photosynthetic organisms to release
Anoxygenic photosynthesis anew. Molecular hydrogen in the bacterial environment is the usual electron donor. Anoxygenic photosynthesis The pigments used to carry out anaerobic photosynthesis are similar to chlorophyll but differ in molecular detail and peak wavelength of light absorbed. Bacteriochlorophylls "a" through "g" absorb electromagnetic photons maximally in the near-infrared within their natural membrane milieu. This differs from chlorophyll a, the predominant plant and cyanobacteria pigment, which has peak absorption wavelength approximately 100 nanometers shorter (in the red portion of the visible spectrum). Some archaea (e.g. "Halobacterium") capture light energy for metabolic function and are thus phototrophic but none are known to