DNA is the smaller unit of heredity which is stored in genes on chromosome in eukaryote. The chromatin structure of chromosome makes it fit into nucleus. The chromosomes carry genes on them which pass on the genetic information to offsprings.
Explanation:
Eukaryotic chromosome is condensed into a compact structure in the nucleus of the cell. This structure is chromatin.
Nucleosome is the subunit of chromatin fibres which are wrapped around by histone proteins or octomers.
Chromosomes have long sequence of DNA in it which has genetic information.
There are 23 chromosomes in human (eukaryotes)
The tight packed form of DNA is heterochromatin. It mainly consist of low density of genes, repetitive sequences and transposable elements.
It protects the chromosome's integrity.
The DNA in the chromosome consists of exon and intron. Exons are the coding sequences and introns are non-coding sequences. Introns are removed by RNA splicing to prevent the disturbance in translation.
There are regulatory sequences on the genes which are responsible for the expression of particular gene. This maintains the correct amount of protein in the cell.