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.
] of most cells. They consist of long strands of a substance called deoxyribonucleic acid, or DNA for short. A section of DNA that has the genetic code for making a particular protein is called a gene.The gene is the unit of inheritance, and each chromosome may have several thousand genes.hey consist of long strands of a substance called deoxyribonucleic acid, or DNA for short. A section of DNA that has the genetic code for making a particular protein is called a gene. The gene is the unit of inheritance, and each chromosome may have several thousand genes.