Editing Motility (section)

==Cellular level ==
{{see also|Cell migration}}
[[File:Subcellular-and-supracellular-mechanical-stress-prescribes-cytoskeleton-behavior-in-Arabidopsis-elife01967v001.ogv|thumb|[[Eukaryote|Eukaryotic]] [[cytoskeleton]]s induce cells to move through liquid and over surfaces, divide into new cells, and the cytoskeleton guides the transport of organelles within the cell. This video captures stained cytoskeletons from the cross section of a leaf of ''[[Arabidopsis thaliana]]''.<ref>{{cite book |last1=Alberts |first1=Bruce |last2=Johnson |first2=Alexander |last3=Lewis |first3=Juian |last4=Raff |first4=Martin |last5=Roberts |first5=Keith |last6=Walter |first6=Peter |title=Molecular biology of the cell |date=2008 |publisher=Garland Science |location=New York |isbn=978-0-8153-4106-2 |page=965 |edition=5th |chapter=16 |quote=For cells to function properly, they must organize themselves in space and interact mechanically with their environment... Eucaryotic cells have developed... the cytoskeleton... pulls the chromosomes apart at mitosis and then splits the dividing cell into two... drives and guides intracellular traffic of organelles... enables cells such as sperm to swim and others, such as fibroblasts and white blood cells, to crawl across surfaces. It exhibits wide range of movement}}</ref>]]

At the cellular level, different modes of movement exist:

* [[amoeboid movement]], a crawling-like movement, which also makes swimming possible<ref>{{cite journal |doi=10.1371/journal.pone.0027532 |pmid=22096590 |pmc=3212573 |title=Amoeboid Cells Use Protrusions for Walking, Gliding and Swimming |journal=PLOS ONE |volume=6 |issue=11 |pages=e27532 |year=2011 |last1=Van Haastert |first1=Peter J. M. |bibcode=2011PLoSO...627532V |doi-access=free }}</ref><ref>{{cite journal |doi=10.1073/pnas.1011900107 |pmid=20921382 |pmc=2973909 |title=On the swimming of Dictyostelium amoebae |journal=Proceedings of the National Academy of Sciences |volume=107 |issue=44 |pages=E165–6 |year=2010 |last1=Bae |first1=A. J. |last2=Bodenschatz |first2=E. |bibcode=2010PNAS..107E.165B |arxiv=1008.3709 |doi-access=free }}</ref>
* [[filopodia]], enabling movement of the [[axon]]al [[growth cone]]<ref name="Gilbert">{{cite book |last1=Gilbert |first1=Scott |title=Developmental biology |date=2006 |publisher=Sinauer Associates, Inc. Publishers |location=Sunderland, Mass. |isbn=9780878932504 |page=395 |edition= 8th.}}</ref>
* [[flagellar motility]], a swimming-like motion (observed for example in [[spermatozoa]], propelled by the regular beat of their [[flagellum]], or the ''[[E. coli]]'' bacterium, which swims by rotating a helical prokaryotic flagellum)
* [[gliding motility]]
* [[swarming motility]]
* [[twitching motility]], a form of motility used by bacteria to crawl over surfaces using grappling hook-like filaments called [[Pilus#Type IV pili|type IV pili]].

Many cells are not motile, for example ''[[Klebsiella pneumoniae]]'' and ''[[Shigella]]'', or under specific circumstances such as ''[[Yersinia pestis]]'' at 37&nbsp;°C.{{Citation needed |date=July 2012}}