you and your Genes

the chemical that chromosomes are made of which is deoxyribonucleic aid. DNA carries the genetic code which controls how an organism works.

Genes are the material in the nuclei of the cells which controls what an organism is like.

It means that the dominant allele will always be expresses for example-

if some one has blue eyes and they have a baby with some one with brown eyes the brown eyes will be expressed in the child because it is dominant.

A recessive allele means it will not be expressed unless there are two recessives.

Huntingtons disease is cuased by a domintant gene, this means that if one parent had it and they have a child it has a 50% chance that it will also develop the disease.

Allele B is normal, allele b causes cystic fibrosis. Allele B is dominant so it is stronger than allele b. So when they are found together the person does not develop the disease.

The combination of alleles that will cause cystic fibrosis is small b, small b.

Therapeutical & Reproductive

- Nucleus is taken out of a human egg cell and is replaced with a nucleus from one of the patients cells.

- The egg cell is triggered to develop into anembryo.

- It is then left for three days

- after five days the cells are removed from the embryo with a pipette.

- stem cells from the embryo.

A chromosome is a thread of genes found in the nucleus.

A nucleus is part of the cell which contains genetic material.

An enzyme is the chemical in the body that speeds up chemical reactions.

Sexual- involves formation of specialised sex cells and fertillisation. Offspring are genetically not identical to the parents.

Asexual- No specialised sex cells, no fertillisation. Offspring are genetically identical to there parents this is called cloning.

A karyotype of an organism is all the chromosomes of a cell.

There are 46 chromosomes in a human body cell and they come in 23 pairs, one of these pairs is sex chromosomes.

A cell of a female organism has two large chromosomes **

A cell of a male organism has one large chromosme and one smaller chromosome Xy

If there are different versions of a gene they are called alleles.