Definition of cyanobacterium
: any of a major group (Cyanobacteria) of photosynthetic bacteria that are single-celled but often form colonies in the form of filaments, sheets, or spheres and are found in diverse environments (such as salt and fresh water, soils, and on rocks) ◆Like other bacteria, cyanobacteria lack a nuclear membrane and membrane-bound organelles and have cell walls containing peptidoglycan . However, cyanobacteria were more commonly grouped with algae in the past because they possess a type of chlorophyll (chlorophyll a) not found in other bacteria and because they produce oxygen as a by-product of photosynthesis. —called also blue-green alga
Origin and Etymology of cyanobacterium
First Known Use: 1974
Medical Definition of cyanobacterium
: any of a major group (Cyanobacteria) of photosynthetic bacteria that produce molecular oxygen and use water as an electron-donating substrate in photosynthesis—called also blue-green alga
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