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They have many features that allow them to survive in these oligotrophic (low-nutrient) and low-light regions, such as the use several nitrogen sources, including nitrate, ammonium, and urea. [6] Their small size and large surface area allows for efficient nutrient acquisition, incident light absorption, and organism growth. [ 7 ]
Some lithotrophic prokaryotes are extremophiles that can survive in nutrient-deprived environments by breaking down inorganic matter. [56] Phototrophic prokaryotes, such as cyanobacteria and Chloroflexia, can engage in photosynthesis to obtain energy from sunlight. This is common among bacteria that form in mats atop geothermal springs.
Their small size and large surface-area-to-volume ratio, gives them an advantage in nutrient-poor water. Still, it is assumed that Prochlorococcus have a very small nutrient requirement. [ 12 ] Moreover, Prochlorococcus have adapted to use sulfolipids instead of phospholipids in their membranes to survive in phosphate deprived environments. [ 13 ]
The sources of energy can be light or chemical compounds; the sources of carbon can be of organic or inorganic origin. [ 1 ] The terms aerobic respiration , anaerobic respiration and fermentation ( substrate-level phosphorylation ) do not refer to primary nutritional groups, but simply reflect the different use of possible electron acceptors in ...
Some dinoflagellates are known to be photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy). [76] Some species are endosymbionts of marine animals and other protists, and play an important part in the biology of coral reefs .
Prokaryotes evolved before eukaryotes, and lack nuclei, mitochondria, and most of the other distinct organelles that characterize the eukaryotic cell. Some unicellular prokaryotes, such as cyanobacteria, form colonies held together by biofilms, and large colonies can create multilayered microbial mats.
Cyanobacteria, the only prokaryotes performing oxygenic photosynthesis and the only prokaryotes that contain two types of photosystems (type I (RCI), also known as Fe-S type, and type II (RCII), also known as quinone type). The seven remaining prokaryotes have anoxygenic photosynthesis and use versions of either type I or type II.
Chloroplasts (from the Greek chloros for green, and plastes for "the one who forms" [31]) are organelles that conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules while freeing oxygen from water in plant and algal cells.