What are chromosomes?
• Other links: • Introduction to chromosome abnormalities at CDO (English) and a translation in German at Leona • The Little Yellow Book, published by Unique • Pictures of chromosomes: • Sketches of all chromosomes, information and links at the Human Genome Research website • Drawing of a chromosome, Nat. Human Genome Research Institute • Graphic of an unbalanced translocation 11;22 (from: An introduction on chromosome disorders, presentation at the conference of European Chromosome 11q Network, 1998, Ede-Lunteren, Netherlands, by Dr. Conny van Ravenswaaij, Klinisch Genetisch Centrum St Radboud ziekenhuis, Nijmegen, Netherlands.) The human body is built out of billions of bricks: the cells, Different types of cells do exist: blood cells, skin cells, muscle cells and so on. All these cells have a nucleus that includes chromosomes. Normally the chromosomes in all cells are alike. In all cells 46 chromosomes occur in 23 identical pairs. The pairs are numbered from big to small. The pairs
Chromosomes are highly condensed rods of Deoxyribonucleic Acid (DNA), the genetic material which contains the building blocks of life. DNA stores important information about the structure of an animal or plant, and it helps direct the organism as it grows and manages daily tasks. Chromosomes serve as the storage for this important material, periodically dividing along with cells and replicating to make copies of the DNA they contain. Chromosomes are also very important in sexual reproduction, as they allow an organism to pass genetic material on to descendants. In organisms with cell nuclei, known as eukaryotes, chromosomes are found inside the nucleus. Most of these organisms have a set of chromosomes which come in pairs. In structural cells, each cell retains a complete set of chromosomes, in what is known as diploid form, referring to the fact that the chromosome set is complete. In cells for sexual reproduction like eggs or sperm, each cell only has half of the parent organism’s ge
Our bodies are made up of billions of cells. Within these cells are structures called chromosomes. There are a total of 46 chromosomes, numbered and arranged in 23 pairs. The last pair consists of the sex determining chromosomes. Females have two X chromosomes and males have an X and a Y chromosome. Each chromosome can be divided into several parts. A special structure called the centromere divides the chromosome into 2 unequal halves, the short arm (p arm) and the long arm, (q arm). Based on special staining patterns each chromosome arm can be divided into individual sections called bands. Each band is given a number designating its location along the chromosome arm. Genes are the very small components of the chromosomes that determine inherited features such as hair, eye, and skin color. In addition genes provide the very important instructions for how we grow and develop. The telomeres are special structures that cap and protect the very ends of each chromosome arm. The area next to
Chromosomes are the packaging for our genetic material, or DNA (deoxyribonucleic acid). DNA carries a specific code that gives instructions to our body on how to grow, develop and function. The instructions are organized into units called genes. Here’s a picture of DNA. There are 46 chromosomes in most cells of the human body. The body is made up of many different cells that are the building blocks for the various tissues and organ systems in our body. If we were able to look inside most cells in a person’s body we would expect to see 46 chromosomes in each cell.
