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Chromatin,Chromosome and Chromatid

Chromatin, Chromosome and Chromatid

Confused mate?? Who ain't confused about the chromatin, chromosome and chromatid especially when we study cell division. Well not anymore.

Remember this: Technically chromatin, chromosome and chromatid are all same; only at various stages the name differ.

Basic info: 

Chromosome/Chromatin/Chromatid = long length of DNA+ histone proteins (see fig)

Cell cycle= Interphase + Cell divison( Prophase+ Metaphase+Anaphase+Telophase)


1. Chromatin = The un-condensed form i.e; long thread like and appear at Interphase and Telophase because when chromosome is uncondensed it is easier for DNA to replicate or translate. If DNA is in condensed form, it can't duplicate or translate.

2. Chromosome = General name. It is highly condensed and has centromere somewhere along the length. Appears during Early Prophase and Anaphase cell divison stage because during prophase to anaphase no need of Translation or replication.

3. Chromatid = Special portions of Chromosome appearing during late prophase to metaphase. During the late prophase stage, a single chromosome longitudinally splits into 2 chromosome but they are attached together by centromere. These each part of this chromosome is called chromatid. Thus each chromosome has 2 chromatid.

But when each chromatid gets seperated during anaphase having each seperate centomere, they are now again called chromosome. Then at telophase, these condensed chromosome starts to uncoil and absorb water to form chromatin again.

For Layman:

 Single Thin Long  Line----------> Single Fat Comapact Line----------> Double Fat Compact Line
      (Chromatin)                                        (chromosome)                                  (Chromatid)                                      
Note: That that" Double Fat compact Line" as a whole is called chromosome but its each part is                     called chromatid 



Homologous Chromosome Vs Non-Homologous Chromosome and 
Sister Chromatid vs Non-sister Chromatid 


We human have 46 chromosome. In this 23 come from father and other 23 from the mother. Lets label them:
Chromosome from Father: F1, F2, F3, F4.............F22, F23
Chromosome from Mother: M1, M2, M3, M4,....... M22, M23 

The chromosome F1 and Chromosome M1,  F2 and M2,  F3 and M3 etc  are homologous chromosome and
the Chromosome F1 and Chromosome M2, F2 and M3 etc are non-homologous chromosome

The F1 and M1 are homologous because both F1 and M1 are same(ie both governs same gene like lets say height gene, eye colour etc which other chromosome can't govern ) with only slight variation in gene pattern between F1 annd M1.

The F1 and M2 are non-homologous because F1 govern "lets say height gene" while M2 govern "lets say skin colour". F1 cant govern skin colour gene and M2 cant govern height gene. If they could have, they would have been homologous .

The chromatids of same chromosome are sister chromatids while the chromatid of different chromosome are non-sister chromatid.


                                                     Any query mate, Feel free to ask? 

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