A Barr body is an inactivated X chromosome.

The human karyotype consists of 22 pairs of autosomes and 1 pair of sex chromosomes totalling 23 pairs altogether.

Heterochromatin contains mostly inactivated genes.

Telomeres are distal extremities of chromosomal arms but centromeres provide a point of attachment for the mitotic spindle.

Northern blotting detects RNA

Southern blotting detects DNA.

Western blotting can be used to detect and quantify proteins