How are the concepts of chromosome, chromatin and chromatids related? In which phase of the cell cycle does DNA duplicate?
Chromatin is a set of filamentous DNA molecules dispersed in the karyoplasm forming euchromatin and heterochromatin portions. Every chromatin filament is a complete chromosome (a DNA molecule, or double helix). The chromatin of the human somatic cell is produced by 46 DNA molecules (22 homologous chromosomes and 1 pair of sex chromosomes).