▁and ▁increase ▁in ▁cell ▁number ▁due ▁to ▁growth . ▁Sub c ulture ▁is ▁therefore ▁used ▁to ▁produce ▁a ▁new ▁culture ▁with ▁a ▁lower ▁density ▁of ▁cells ▁than ▁the ▁origin ating ▁culture , ▁fresh ▁nut ri ents ▁and ▁no ▁to xic ▁met abol ites ▁allowing ▁continued ▁growth ▁of ▁the ▁cells ▁without ▁risk ▁of ▁cell ▁death . ▁Sub c ulture ▁is ▁important ▁for ▁both ▁pro l ifer ating ▁( e . g . ▁a ▁micro organ ism ▁like ▁E . ▁col i ) ▁and ▁non - pro l ifer ating ▁( e . g . ▁termin ally ▁differenti ated ▁white ▁blood ▁cells ) ▁cells . ▁ ▁Typ ically , ▁sub c ulture ▁is ▁from ▁a ▁culture ▁of ▁a ▁certain ▁volume ▁into ▁fresh ▁growth ▁medium ▁of ▁equal ▁volume , ▁this ▁allows ▁long - term ▁maintenance ▁of ▁the ▁cell ▁line . ▁Sub c ulture ▁into ▁a ▁larger ▁volume ▁of ▁growth ▁medium ▁is ▁used ▁when ▁wanting ▁to ▁increase ▁the ▁number ▁of ▁cells ▁for , ▁for ▁example , ▁use ▁in ▁an ▁industrial ▁process ▁or ▁scientific ▁experiment . ▁ ▁Pass age ▁number ▁It ▁is ▁often ▁important ▁to ▁record ▁the ▁approximate ▁number ▁of ▁divisions ▁cells ▁have ▁had ▁in ▁culture ▁by ▁recording ▁the ▁number ▁of ▁pass ages ▁or ▁sub c ult ures . ▁In ▁the ▁case ▁of ▁plant ▁t issue ▁cells ▁som ac l onal ▁variation ▁may ▁arise ▁over ▁long ▁periods ▁in ▁culture . ▁Similarly ▁in ▁m amm al ian ▁cell ▁lines ▁chrom os om al ▁aber r ations ▁have ▁a ▁t endency ▁to ▁increase ▁over ▁time . ▁For ▁micro organ isms