Editing Nutrition (section)

=== Prokaryote ===
{{Further|Microbial metabolism}}
[[File:Metabolism-en.svg|thumb|Simplified view of [[Metabolism|cellular metabolism]]]]
[[Prokaryote]]s, including [[bacteria]] and [[archaea]], vary greatly in how they obtain nutrients across nutritional groups. Prokaryotes can only transport soluble compounds across their cell envelopes, but they can break down chemical components around them. Some lithotrophic prokaryotes are [[extremophile]]s that can survive in nutrient-deprived environments by breaking down inorganic matter.<ref>{{cite book |doi=10.1016/B978-044452748-6.00164-4 |chapter=Geology, Life and Habitability |title=Treatise on Geophysics |date=2007 |last1=Southam |first1=G. |last2=Westall |first2=F. |pages=421–437 |isbn=978-0-444-52748-6 |chapter-url=https://elib.dlr.de/97967/1/10-14-Geology-Life-and-Habitability_2015_Treatise-on-Geophysics-Second-Edition-.pdf }}</ref> 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. Phototrophic prokaryotes typically obtain carbon from assimilating carbon dioxide through the [[Calvin cycle]].<ref>{{cite book |doi=10.1007/0-387-30742-7_3 |chapter=The Phototrophic Way of Life |title=The Prokaryotes |date=2006 |last1=Overmann |first1=Jörg |last2=Garcia-Pichel |first2=Ferrau |pages=32–85 |isbn=978-0-387-25492-0 }}</ref>

Some prokaryotes, such as ''[[Bdellovibrio]]'' and [[Ensifer (bacterium)|''Ensifer'']], are predatory and feed on other single-celled organisms. Predatory prokaryotes seek out other organisms through [[chemotaxis]] or random collision, merge with the organism, degrade it, and absorb the released nutrients. Predatory strategies of prokaryotes include attaching to the outer surface of the organism and degrading it externally, entering the cytoplasm of the organism, or by entering the [[Periplasm|periplasmic space]] of the organism. Groups of predatory prokaryotes may forgo attachment by collectively producing [[Hydrolysis|hydrolytic]] enzymes.<ref>{{cite journal |last1=Martin |first1=Mark O. |title=Predatory prokaryotes: an emerging research opportunity |journal=Journal of Molecular Microbiology and Biotechnology |date=September 2002 |volume=4 |issue=5 |pages=467–477 |pmid=12432957 }}</ref>