- Created by: naomi mann
- Created on: 23-12-08 11:06
What is DNA?
the chemical that chromosomes are made of which is deoxyribonucleic aid. DNA carries the genetic code which controls how an organism works.
What is a gene?
Genes are the material in the nuclei of the cells which controls what an organism is like.
What does it mean when there is a dominant allele?
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.
What does it mean if there is a recessive allele?
A recessive allele means it will not be expressed unless there are two recessives.
Huntingtons disorder- what is it caused by?
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.
Cystic Fibrosis- what causes it? (explain)
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.
What are the two types if cloning?
Therapeutical & Reproductive
What is the process for cloning?
- 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.
What is a chromosome?
A chromosome is a thread of genes found in the nucleus.
What is a nucleus?
A nucleus is part of the cell which contains genetic material.
What is an Enzyme?
An enzyme is the chemical in the body that speeds up chemical reactions.
What are the two types of reproduction and what do
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.
What is a karyotype?
A karyotype of an organism is all the chromosomes of a cell.
How many chromosomes are in a human body cell?
There are 46 chromosomes in a human body cell and they come in 23 pairs, one of these pairs is sex chromosomes.
What are female/Male cells made up of?
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
What is the name for a gene if there are different
If there are different versions of a gene they are called alleles.