Chromosome- Structure, Types and Functions In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure. They appear as rod shaped dark stained bodies during the metaphase stage of mitosis when cells are stained with a suitable basic dye and viewed under a light microscope. An organism’s genome is typically divided among a number of long DNA molecules called chromosomes. While prokaryotic genomes are typically made up of only one chromosome, eukaryotic genomes may have many. Human cells, for example, have 23 pairs of nuclear chromosomes (46 total) plus one mitochondrial chromosome. Chromosome breakage is the physical breakage of subunits of a chromosome. It is usually followed by reunion (frequently at a foreign site, resulting in a chromosome unlike the original). Breakage and reunion of homologous chromosomes during meiosis are the basis for the classical model of crossing over, which results in unexpected types of offspring of a mating. Chromosome- Structure, Types and Functions In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.
