Chromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA is the material that holds genes . It is the building block of the human body.
A gene is a short piece of DNA. Genes tell the body how to build specific proteins. There are about 20,000 genes in each cell of the human body. T...
Chromosomes also contain proteins that help DNA exist in the proper form.
Chromosomes come in pairs. Normally, each cell in the human body has 23 pairs of chromosomes (46 total chromosomes). Half come from the mother; the other half come from the father.
Two of the chromosomes (the X and the Y chromosome) determine if you are born a boy or a girl (your gender). They are called sex chromosomes:
- Females have 2 X chromosomes.
- Males have 1 X and 1 Y chromosome.
The mother gives an X chromosome to the child. The father may contribute an X or a Y. The chromosome from the father determines if the baby is a girl or a boy.
The remaining chromosomes are called autosomal chromosomes. They are known as chromosome pairs 1 through 22.
Dorland's Online Medical Dictionary. Available at: www.dorlands.com/def.jsp?id=100021078. Accessed April 27, 2015.
Stein CK. Applications of Cytogenetics in Modern Pathology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 68.
Chromosomes and DNA - illustration
Humans typically have 23 pairs chromosomes, or 46 chromosomes in total. Chromosomes are made up of long strands of DNA, which contain all the body's genes.
Chromosomes and DNA
Review Date: 4/20/2015
Reviewed By: Chad Haldeman-Englert, MD, FACMG, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.