1. Nucleus contains genetic information in the form of chromosomes which are DNA molecules associated with proteins.
2. In a non-dividing cell, the chromosomes appear as thread like network and cannot be identified individually. This network is called chromatin material.
3. The chromatin material contains DNA, histone and non-histone proteins and RNA.
4. In some regions of chromatin, DNA is more and is genetically active called euchromatin.
5. Some regions that contain more of proteins and less DNA and are genetically inert, are called heterochromatin.
[Note: Heterochromatin is a region in chromatin that is highly compacted during interphase and is generally not accessible for transcription of genes.]
