4. Chromosome structure

Figure 27: The human karyotype

Figure 27: The human karyotype

4.2 The eukaryotic chromosome

Eukaryotic chromosomes are always linear and are associated with proteins.

A certain amount of DNA condensation occurs from the presence of proteins.

Chromatin

Chromatin is the association of DNA with proteins. There are three levels of chromatin condensation.

  • 1st level of chromatin condensation: the nucleosome fiber

  • 2nd level of chromatin condensation: the thick fiber

  • 3rd level of chromatin condensation: the heterochromatin