Editing Cytoplasm (section)

==Constituents==
The three major elements of the cytoplasm are the [[cytosol]], [[organelle]]s and [[cytoplasmic inclusions|inclusions]].

===Cytosol===
{{main|Cytosol}}

The cytosol is the portion of the cytoplasm not contained within membrane-bound organelles. Cytosol makes up about 70% of the cell volume and is a complex mixture of [[cytoskeleton]] filaments, dissolved molecules, and water. The cytosol's filaments include the [[protein filament]]s such as [[actin filament]]s and [[microtubule]]s that make up the cytoskeleton, as well as soluble [[protein]]s and small structures such as [[ribosome]]s, [[proteasome]]s, and the mysterious [[Vault (organelle)|vault complexes]].<ref>{{Cite journal |vauthors=van Zon A, Mossink MH, Scheper RJ, Sonneveld P, Wiemer EA |date=September 2003 |title=The vault complex |journal=Cellular and Molecular Life Sciences |volume=60 |issue=9 |pages=1828–37 |doi=10.1007/s00018-003-3030-y |pmc=11138885 |pmid=14523546 |s2cid=21196262}}</ref> The inner, granular and more fluid portion of the cytoplasm is referred to as endoplasm.[[File:Localisations02eng.jpg|thumb|right|250px|Proteins in different [[cellular compartment]]s and structures [[Protein tag#Protein tags|tagged]] with [[green fluorescent protein]]]]

Due to this network of fibres and high concentrations of dissolved [[macromolecule]]s, such as [[protein]]s, an effect called [[macromolecular crowding]] occurs and the cytosol does not act as an [[ideal solution]]. This crowding effect alters how the components of the cytosol interact with each other.

===Organelles===
{{main|Organelle}}
Organelles (literally "little organs") are usually membrane-bound structures inside the cell that have specific functions. Some major organelles that are suspended in the cytosol are the [[mitochondria]], the [[endoplasmic reticulum]], the [[Golgi apparatus]], [[vacuole]]s, [[lysosome]]s, and in plant cells, [[chloroplast]]s.

===Cytoplasmic inclusions===
{{main|Cytoplasmic inclusion}}
The inclusions are small particles of insoluble substances suspended in the cytosol. A huge range of inclusions exist in different cell types, and range from crystals of [[calcium oxalate]] or [[silicon dioxide]] in plants,<ref name="Prychid1999">{{Cite journal |last=Prychid, Christina J. |last2=Rudall, Paula J. |year=1999 |title=Calcium Oxalate Crystals in Monocotyledons: A Review of their Structure and Systematics |url=https://academic.oup.com/aob/article-pdf/84/6/725/7983834/840725.pdf |journal=Annals of Botany |volume=84 |issue=6 |pages=725–739 |doi=10.1006/anbo.1999.0975 |doi-access=free}}</ref><ref name="Prychid2003">{{Cite journal |last3=Gregory, M. |vauthors=Prychid CJ, Rudall PJ |year=2004 |title=Systematics and Biology of Silica Bodies in Monocotyledons |journal=The Botanical Review |volume=69 |issue=4 |pages=377–440 |doi=10.1663/0006-8101(2004)069[0377:SABOSB]2.0.CO;2 |jstor=4354467 |s2cid=24520433}}</ref> to granules of energy-storage materials such as [[starch]],<ref>{{Cite journal |vauthors=Ball SG, Morell MK |year=2003 |title=From bacterial glycogen to starch: understanding the biogenesis of the plant starch granule |journal=Annual Review of Plant Biology |volume=54 |pages=207–233 |doi=10.1146/annurev.arplant.54.031902.134927 |pmid=14502990}}</ref> [[glycogen]],<ref>{{Cite journal |vauthors=Shearer J, Graham TE |date=April 2002 |title=New perspectives on the storage and organization of muscle glycogen |journal=Canadian Journal of Applied Physiology |volume=27 |issue=2 |pages=179–203 |doi=10.1139/h02-012 |pmid=12179957}}</ref> or [[polyhydroxybutyrate]].<ref>{{Cite journal |vauthors=Anderson AJ, Dawes EA |date=December 1990 |title=Occurrence, metabolism, metabolic role, and industrial uses of bacterial polyhydroxyalkanoates |journal=Microbiological Reviews |volume=54 |issue=4 |pages=450–472 |doi=10.1128/MMBR.54.4.450-472.1990 |pmc=372789 |pmid=2087222}}</ref> A particularly widespread example are [[lipid droplet]]s, which are spherical droplets composed of lipids and proteins that are used in both prokaryotes and eukaryotes as a way of storing lipids such as [[fatty acid]]s and [[sterol]]s.<ref>{{Cite journal |vauthors=Murphy DJ |date=September 2001 |title=The biogenesis and functions of lipid bodies in animals, plants and microorganisms |journal=Progress in Lipid Research |volume=40 |issue=5 |pages=325–438 |doi=10.1016/S0163-7827(01)00013-3 |pmid=11470496}}</ref> Lipid droplets make up much of the volume of [[adipocyte]]s, which are specialized lipid-storage cells, but they are also found in a range of other cell types.

===Controversy and research===
The cytoplasm, mitochondria, and most organelles are contributions to the cell from the maternal gamete. Contrary to the older information that disregards any notion of the cytoplasm being active, new research has shown it to be in control of movement and flow of nutrients in and out of the cell by [[Viscoelasticity|viscoplastic behavior]] and a measure of the reciprocal rate of bond breakage within the cytoplasmic network.<ref name="Viscoplasticity">{{Cite journal |vauthors=Feneberg W, Westphal M, Sackmann E |date=August 2001 |title=Dictyostelium cells' cytoplasm as an active viscoplastic body |journal=European Biophysics Journal |volume=30 |issue=4 |pages=284–94 |doi=10.1007/s002490100135 |pmid=11548131 |s2cid=9782043}}</ref>

The material properties of the cytoplasm remain an ongoing investigation. A method of determining the mechanical behaviour of living cell mammalian cytoplasm with the aid of [[optical tweezers]] has been described.<ref name="pmid28827333">{{Cite journal |vauthors=Hu J, Jafari S, Han Y, Grodzinsky AJ, Cai S, Guo M |date=September 2017 |title=Size- and speed-dependent mechanical behavior in living mammalian cytoplasm |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=114 |issue=36 |pages=9529–9534 |bibcode=2017PNAS..114.9529H |doi=10.1073/pnas.1702488114 |pmc=5594647 |pmid=28827333 |doi-access=free}}</ref>