Editing Cell (biology) (section)

=== Genetic material ===

{{main|DNA|RNA}}

[[File:DNA orbit animated.gif|thumb|[[DNA|Deoxyribonucleic acid]] (DNA)]]

Two different kinds of genetic material exist: [[DNA|deoxyribonucleic acid]] (DNA) and [[RNA|ribonucleic acid]] (RNA). Cells use DNA for their long-term information storage. The biological information contained in an organism is [[Genetic code|encoded]] in its DNA sequence.<ref name="NCBI"/> RNA is used for information transport (e.g., [[mRNA]]) and [[enzyme|enzymatic]] functions (e.g., [[ribosome|ribosomal]] RNA). [[Transfer RNA]] (tRNA) molecules are used to add amino acids during protein [[Translation (biology)|translation]].

Prokaryotic genetic material is organized in a simple [[circular bacterial chromosome]] in the [[nucleoid region]] of the cytoplasm. Eukaryotic genetic material is divided into different,<ref name="NCBI"/> linear molecules called [[chromosome]]s inside a discrete nucleus, usually with additional genetic material in some organelles like [[mitochondria]] and [[chloroplasts]] (see [[endosymbiotic theory]]).

A [[human cell]] has genetic material contained in the [[cell nucleus]] (the [[genome|nuclear genome]]) and in the mitochondria (the [[mitochondrial genome]]). In humans, the nuclear genome is divided into 46 linear DNA molecules called [[chromosome]]s, including 22 [[homologous chromosome]] pairs and a pair of [[sex chromosomes]]. The mitochondrial genome is a circular DNA molecule distinct from nuclear DNA. Although the [[mitochondrial DNA]] is very small compared to nuclear chromosomes,<ref name="NCBI"/> it codes for 13 proteins involved in mitochondrial energy production and specific tRNAs.

Foreign genetic material (most commonly DNA) can also be artificially introduced into the cell by a process called [[transfection]]. This can be transient, if the DNA is not inserted into the cell's [[genome]], or stable, if it is. Certain [[virus]]es also insert their genetic material into the genome.