Sunday, August 17, 2008 ; ♥
Mutagens
A mutation is a permanent change in the DNA sequence of a gene. Sometimes mutations in DNA can cause changes in the way a cell behaves. This is because genes contain the instructions necessary for a cell to work. If some of the instructions to the cell are wrong, then the cell may not know what it is supposed to do!
There are two ways in which DNA can become mutated:
- Mutations can be inherited. This means that if a parent has a mutation in his or her DNA, then the mutation is passed on to his or her children.
- Mutations can be acquired. This happens when environmental agents damage DNA, or when mistakes occur when a cell copies its DNA prior to cell division.
As many mutations cause cancer, mutagens are typically also carcinogens.
Not all mutations are caused by mutagens: So-called "spontaneous mutations" occur due to errors in DNA replication, repair and recombination.
Examples of mutations
- Ionizing radiation, for example Ultraviolet light, gamma rays and alpha particles
- Base analogs, which can substitute for DNA bases and cause copying errors
- Delaminating agents such as Nitrous acid
- Intercalating agents such as Ethidium bromide
- Alkylating agents such as Bromouracil
- Transposons, sections of DNA that undergo autonomous fragment relocation/multiplication
- Some natural plant alkaloids, such as those from Vinca species.
- Bromine and some of its compounds
- Sodium azide
- Psoralen combined with ultraviolet radiation causes DNA crosslinking and hence chromosome breakage
This is huge topic .
For more information please read up at wikipedia .
http://en.wikipedia.org/wiki/Genetics Read this too :)
Labels: Perfectionist
