Cold sores are caused by a herpes virus. There are eight different kinds of human herpes viruses. Only two of these, herpes simplex types 1 and 2, can cause cold sores. It is commonly believed that herpes simplex virus type 1 infects above the waist and herpes simplex virus type 2 infects below the waist.
The DNA is tightly coiled many times around proteins called histones that support the chromosome structure. The bound DNA units are called nucleosomes. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two sex chromosomes.Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers.he bound DNA units are called nucleosomes. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two sex chromosomes.
A chromosome is a DNA molecule with part or all of the genetic material of an organism. Chromosomes are normally visible under a light microscope only when the cell is undergoing the metaphase of cell division. Before this happens, every chromosome is copied once, and the copy is joined to the original by a centromere, resulting in an X-shaped structure. The original chromosome and the copy are now called sister chromatids. During metaphase the X-shape structure is called a metaphase chromosome.