How theory of chromosome-chromatids-chromatin connected

Question

How are the theory of chromosome, chromatids and chromatin connected? In which stage of the cell cycle does DNA duplicate?

Answer 1

Chromatin is a set of filamentous DNA molecules scattered in the karyoplasm making heterochromatin and euchromatin portions. Each chromatin filament is a whole chromosome (that is, a DNA molecule, or double helix). The chromatin of human somatic cell is made by 46 DNA molecules (that is, 22 homologous chromosomes and 1 pair of sex chromosomes).

In interphase, cell prepares itself for duplication and division of DNA molecules takes place. The duplication of each and every DNA molecule makes two similar DNA double helix bound by a structure termed as centromere. In this stage each and every similar chromosome of such pairs is termed as chromatid. It is as well through the interphase which the chromatids start to condensate supposing the thicker and shorter shape typical of chromosome illustrations. Therefore the stage of the cell cycle in which DNA duplicates is the interphase.

Some of the biology textbooks state the chromosome a unique filament of chromatin and also the condensed structure made up of two similar chromatids after the DNA duplication. Rigorously the pair of similar chromatids bound in the centromere is two copies of similar chromosome and thus they are two identical chromosomes (and not just one).