Editing Human body (section)

===Cells===
{{See also|List of distinct cell types in the adult human body}}
The body contains trillions of [[Cell (biology)|cells]], the fundamental unit of life. At maturity, there are roughly 30 trillion cells, and 38 trillion bacteria in the body,<ref name="sender-et-al">{{Cite journal |last1=Sender |first1=Ron |last2=Fuchs |first2=Shai |last3=Milo |first3=Ron |year=2016 |title=Revised estimates for the number of human and bacteria cells in the body |journal=PLOS Biology |volume=14 |issue=8 |pages=e1002533 |biorxiv=10.1101/036103 |doi=10.1371/journal.pbio.1002533 |pmc=4991899 |pmid=27541692 |doi-access=free |issn = 1544-9173}}</ref><ref>{{Cite journal |last1=Hatton |first1=Ian A. |last2=Galbraith |first2=Eric D. |last3=Merleau |first3=Nono S. C. |last4=Miettinen |first4=Teemu P. |last5=Smith |first5=Benjamin McDonald |last6=Shander |first6=Jeffery A. |date=2023-09-26 |title=The human cell count and size distribution |journal=Proceedings of the National Academy of Sciences |language=en |volume=120 |issue=39 |pages=e2303077120 |doi=10.1073/pnas.2303077120 |doi-access=free |issn=0027-8424 |pmc=10523466 |pmid=37722043|bibcode=2023PNAS..12003077H }}</ref> an estimate arrived at by totaling the cell numbers of all the [[Organ (biology)|organs]] of the body and [[List of human cell types|cell types]]. The skin of the body is also host to billions of commensal organisms as well as immune cells.<ref name="Sfriso">{{cite journal |last1=Sfriso |first1=R |last2=Egert |first2=M |last3=Gempeler |first3=M |last4=Voegeli |first4=R |last5=Campiche |first5=R |title=Revealing the secret life of skin - with the microbiome you never walk alone. |journal=International Journal of Cosmetic Science |date=April 2020 |volume=42 |issue=2 |pages=116–126 |doi=10.1111/ics.12594 |pmid=31743445|pmc=7155096 }}</ref>  Not all parts of the body are made from cells. Cells sit in an [[extracellular matrix]] that consists of [[protein]]s such as [[collagen]], surrounded by extracellular fluids.

Each of the cells of the human body experiences, on average, tens of thousands of [[DNA damage (naturally occurring)|DNA damages]] per day.<ref name = Jackson2009>{{cite journal |vauthors=Jackson SP, Bartek J |title=The DNA-damage response in human biology and disease |journal=Nature |volume=461 |issue=7267 |pages=1071–8 |date=October 2009 |pmid=19847258 |pmc=2906700 |doi=10.1038/nature08467 |bibcode=2009Natur.461.1071J |url=}}</ref>  These damages can block [[human genome|genome]] replication or genome transcription, and if they are not [[DNA repair|repaired]] or are repaired incorrectly, they may lead to [[mutation]]s, or other genome alterations that threaten cell viability.<ref name = Jackson2009/> 

====Genome====
{{Main|Genome}}
{{See also|Genetics}}
[[File:Genome-fr.svg|thumb|[[Genome]]]]
Cells in the body function because of [[DNA]]. DNA sits within the [[Cell nucleus|nucleus of a cell]]. Here, parts of DNA are [[Transcription (biology)|copied]] and sent to the body of the cell via [[RNA]].{{sfn|Ganong's|2016|p=16}} The RNA is then used to [[translation (biology)|create]] [[protein]]s, which form the basis for cells, their activity, and their products. Proteins dictate cell function and gene expression, a cell is able to self-regulate by the amount of proteins produced.<ref>{{Cite web|title=Gene Expression {{!}} Learn Science at Scitable|url=http://www.nature.com/scitable/topicpage/gene-expression-14121669|website=www.nature.com|language=en|url-status=dead|archive-url=https://web.archive.org/web/20101031053632/http://www.nature.com/scitable/topicpage/gene-expression-14121669|archive-date=31 October 2010|access-date=29 July 2017}}</ref> However, not all cells have DNA; some cells such as mature [[Red blood cell|red blood cells]] lose their nucleus as they mature.