Structure: Metaphasic chromosome lias two sister chromatids which are identical halves.
(a) Each chromatid in turn is made up of subchromatids called chromonemata.
(b) Chromatids are held together at one point called centromere. It is also called primary constriction.
(c) Additional narrow areas called `2^(@)`-constrictions are present.
(d) Some of the `2^(@)`-constrictions are called nucleolar organizer because they are necessary for formation of nucleolus.
(e) Short spherical structure beyond nucleolar organizer is called satellite.
(f) Tip of chromosomes is called telomere. It prevents sticking of chromosomes ends.
(g) Surface of chromosome bears number of small smellings called chromomeres.
