Biology-You and your genes (B1)

 Genes; A nucleus contains chromosones and within them chromosones they are all made up of genes. Different verisons of the same gene are called alleles which determine our main features like our hair and eye colour.

DNA; The nucleus controls the activites of the cell. The instructions for how an organism develops are found in the nuclei of its cell.

Chromosone; Chromosones are structures found in the nucleus in a cell. They consist of a long strand of a substance called deoxyribonucleic acid (DNA for short). A section of DNA that has the gentic code for making a particualr protein is called a gene.

Gene; A basic unit of genetic material inherited from our parents. A gene is a section of a DNA strand.This controls the cell's chemistry.

DNA; The material inside the nucleus of cells.This carries genetic information given to us by our parents. DNA is short for deoxyricbonucleic acid.

Chromosones; Rod shaped bodies found the nucleus of a cell. These contain genetic information DNA^.

Nucleus; Controls what happens inside the cell. Chromosones are structures found in the nucleus of most cells.

-When a sperm and egg cell meet together you have a fertilised egg. This egg contains 23 pairs of chromosomes. Sex chromosones are responsible for certain genetic traits.

Human body cells each contain 23 pairs of chromosomes. Parents pass their genes onto their offspring in their sex cells.

There are different versions of genes these are called alleles.

Stem cells; There are two types of stem cell. Adult stem cells;unspecialised cells that can develop into many (not all) types of cells. Embryonic stem cells;These can develop into any type of cell.    During development of an embryo, most cells are specialised. Later they can not change to any other cell. In an embryon there is a stem cell and this cell can grow into any type of cell found in the body so that they are not specialised.Stem cells can be used for; making new brain cells for treating people with parkinson's disease, buliding bones and cartilage, repairing damaged immune systems & making replacement heart valves.