Editing Foraminifera (section)

==Anatomy==
The most striking aspect of most foraminifera are their hard shells, or tests. These may consist of one of multiple chambers, and may be composed of protein, sediment particles, calcite, aragonite, or (in one case) silica.<ref name="Sen_Gupta02" /> Some foraminifera lack tests entirely.<ref name=":18">{{Cite journal|last1=Pawlowski|first1=Jan|last2=Bolivar|first2=Ignacio|last3=Fahrni|first3=Jose F.|last4=Vargas|first4=Colomban De|last5=Bowser|first5=Samuel S.|date=1999|title=Molecular Evidence That Reticulomyxa Filosa Is A Freshwater Naked Foraminifer|journal=Journal of Eukaryotic Microbiology|language=en|volume=46|issue=6|pages=612–617|doi=10.1111/j.1550-7408.1999.tb05137.x|pmid=10568034|s2cid=36497475|issn=1550-7408}}</ref> Unlike other shell-secreting organisms, such as [[Mollusca|molluscs]] or [[coral]]s, the tests of foraminifera are located inside the [[cell membrane]], within the [[protoplasm]]. The organelles of the cell are located within the {{Not a typo|compartment(s)}} of the test, and the {{Not a typo|hole(s)}} of the test allow the transfer of material from the pseudopodia to the internal cell and back.<ref name=Saraswati2016>{{Citation|last1=Saraswati|first1=Pratul Kumar|title=Calcareous-Walled Microfossils|date=2016|work=Micropaleontology: Principles and Applications|pages=81–119|editor-last=Saraswati|editor-first=Pratul Kumar|publisher=Springer International Publishing|language=en|doi=10.1007/978-3-319-14574-7_6|isbn=978-3-319-14574-7|last2=Srinivasan|first2=M. S.|editor2-last=Srinivasan|editor2-first=M.S.}}</ref>

The foraminiferal cell is divided into granular endoplasm and transparent ectoplasm from which a [[pseudopodia]]l net may emerge through a single opening or through many perforations in the test. Individual pseudopods characteristically have small granules streaming in both directions.<ref name="Sen_Gupta83">{{cite book|last=Sen Gupta|first=Barun K.|title=Foraminifera: notes for a short course organized by M.A. Buzas and B.K. Sen Gupta|publisher=University of Tennessee, Dept. of Geological Sciences|year=1982|isbn=978-0910249058|editor-last=Broadhead|editor-first=T.W.|series=Studies in Geology|volume=6|pages=37–50|chapter=Ecology of benthic Foraminifera|oclc=9276403|chapter-url=https://books.google.com/books?id=33hOAQAAIAAJ}}</ref> Foraminifera are unique in having ''granuloreticulose pseudopodia''; that is, their pseudopodia appear granular under the microscope; these pseudopodia are often elongate and may split and rejoin each other. These can be extended and retracted to suit the needs of the cell. The pseudopods are used for locomotion, anchoring, excretion, test construction and in capturing food, which consists of small organisms such as diatoms or bacteria.<ref name="Hemleben">{{cite book|last1=Hemleben|first1=C.|url=https://books.google.com/books?id=NaHOmAEACAAJ|title=Modern Planktonic Foraminifera|last2=Anderson|first2=O.R.|last3=Spindler|first3=M.|publisher=Springer-Verlag|year=1989|isbn=978-3-540-96815-3}}</ref><ref name=Saraswati2016 />

Aside from the tests, foraminiferal cells are supported by a [[cytoskeleton]] of microtubules, which are loosely arranged without the structure seen in other amoeboids. Forams have evolved special cellular mechanisms to quickly assemble and disassemble microtubules, allowing for the rapid formation and retraction of elongated pseudopodia.<ref name="Sen_Gupta02" />

[[File:2023 Foram.svg|thumb|center|upright=2|{{center|Detailed diagram of foraminifera morphology}}{{ordered list|Test|Proloculus (first chamber)|Chambers|Foramen (older apertures)|Endoplasm|Lipid globule|
[[Cell nucleus|Nucleus]]|
[[Nucleolus]]|
[[Endoplasmic reticulum]], the transport network for molecules going to specific parts of the cell|
Annular [[Lamella (cell biology)|lamellae]]|
[[Mitochondria|Mitochondrion]], creates [[Adenosine triphosphate|ATP]] (energy) for the cell|
Nascent annular lamellae|
[[Golgi apparatus]]; modifies [[protein]]s and sends them out of the cell|
[[Food vacuole|Digestive vacuole]]|
[[Peroxisome]], generates and scavenges hydrogen peroxide|
[[Phagosome|Phagocytic vacuole]]|
[[Lysosome]], holds enzymes|
Adhesive substance vesicle|
Aperture (opening of newest chamber)|
[[Ectoplasm (cell biology)|Ectoplasm]]|
Reticulopodia|
Adhesive granules|
Prey}}]]

In the gamont (sexual form), foraminifera generally have only a single nucleus, while the agamont (asexual form) tends to have multiple nuclei. In at least some species the nuclei are dimorphic, with the somatic nuclei containing three times as much protein and RNA than the generative nuclei. However, nuclear anatomy seems to be highly diverse.<ref>{{Cite journal|last=Grell|first=K. G.|date=1979-01-01|title=Cytogenetic systems and evolution in foraminifera|url=http://dx.doi.org/10.2113/gsjfr.9.1.1|journal=The Journal of Foraminiferal Research|volume=9|issue=1|pages=1–13|doi=10.2113/gsjfr.9.1.1|bibcode=1979JForR...9....1G |issn=0096-1191|url-access=subscription}}</ref> The nuclei are not necessarily confined to one chamber in multi-chambered species. Nuclei can be spherical or have many lobes. Nuclei are typically 30-50&nbsp;μm in diameter.<ref name=":19">{{Cite journal|date=2018-01-01|title=An overview of cellular ultrastructure in benthic foraminifera: New observations of rotalid species in the context of existing literature|journal=Marine Micropaleontology|language=en|volume=138|pages=12–32|doi=10.1016/j.marmicro.2017.10.005|issn=0377-8398|last1=Lekieffre|first1=Charlotte|last2=Bernhard|first2=Joan M.|last3=Mabilleau|first3=Guillaume|last4=Filipsson|first4=Helena L.|last5=Meibom|first5=Anders|last6=Geslin|first6=Emmanuelle|bibcode=2018MarMP.138...12L |doi-access=free|hdl=1912/9530|hdl-access=free}}</ref>

Some species of foraminifera have large, empty vacuoles within their cells; the exact purpose of these is unclear, but they have been suggested to function as a reservoir of nitrate.<ref name=":19" />

Mitochondria are distributed evenly throughout the cell, though in some species they are concentrated under the pores and around the external margin of the cell. This has been hypothesised to be an adaptation to low-oxygen environments.<ref name=":19" />

Several species of [[Xenophyophorea|xenophyophore]] have been found to have unusually high concentrations of [[Radionuclide|radioactive isotopes]] within their cells, among the highest of any eukaryote. The purpose of this is unknown.<ref>{{Cite journal|last=Domanov|first=M. M.|date=July 2015|title=Natural 226Ra and 232Th radionuclides in xenophyophores of the Pacific Ocean|url=http://link.springer.com/10.1134/S0016702915070034|journal=Geochemistry International|language=en|volume=53|issue=7|pages=664–669|doi=10.1134/S0016702915070034|bibcode=2015GeocI..53..664D |s2cid=127121951|issn=0016-7029|url-access=subscription}}</ref>