known that there are 100-1,000,000 molecular lesions occurred in a human body per day. I6 If the molecular lesion is occurred in dna. that is called a mutation The molecular lesion might cause the mutation as well. When the molecular lesion occurs, the enzyme in the cells is disable to e the lesion, and repair the lesion by a mechanism called DNA repair. If the cell will recos repair the dna damage the cell might became an irreversible state of dormancy known as senescence, or perform cell suicide, also known as apoptosis or programmed cell death, or might cause mutation in the cell [7 The chemical mutagen disturbs the dNA replication and causes the changes in DNA information Mutation rates in higher eukaryotes are roughly 0. 1-100 per genome per sexual generation but are currently indistinguishable from 1/300 per cell division per effective genome. 8 When the cell is mutated, there are many cases for the cell. Major probabil ity of the mutation effects are just silent, it means there will be no effect, since there are a lot of introns in human gene. Sometimes, the mutation will cause the difference in surviving ab il ities of the cell. when these kinds of changes occur. in worst case, the cancer or tumor might be occurred LITERATURE CITED 1.http://sciencejrank.org/pages/4529/mutagen.htm 2.http:/www.microbiologyprocedure.com/gene-mutation/spontaneous-mutations.htm 4. Brusick, David. Principles of Genetic Toxicology 2nd ed. New York: Plenum Press, 1987. 5.http://en.wikipediaorg/wiki/mutagen 6. Lodish H, Berk A, Matsudaira P Kaiser CA, Krieger M, Scott MP Zipursky sL, Darnell J (2004). Molecular Biology of the Cell, p963. WH Freeman: New York, NY. 5th ed. 7.http://en.wikipedia.org/wiki/dna_repair#cite_notE-lodiSh-0 8. John W. Drake, Brian Charlesworth Deborah Charlesworth and James f crow Rate of spontaneous mutation. Genetics, VoL. 148, 1667-1686, April 1998, Copyright o 1998known that there are 100~1,000,000 molecular lesions occurred in a human body per day. [6] If the molecular lesion is occurred in DNA, that is called a mutation. The molecular lesion might cause the mutation as well. When the molecular lesion occurs, the enzyme in the cells will recognize the lesion, and repair the lesion by a mechanism called DNA repair. If the cell is disable to repair the DNA damage, the cell might became an irreversible state of dormancy, known as senescence, or perform cell suicide, also known as apoptosis or programmed cell death, or might cause mutation in the cell. [7] The chemical mutagen disturbs the DNA replication and causes the changes in DNA information. Mutation ratesin higher eukaryotes are roughly 0.1–100 per genome per sexual generation but are currently indistinguishable from 1/300 per cell division per effective genome. [8] When the cell is mutated, there are many cases for the cell. Major probability of the mutation effects are just silent, it means there will be no effect, since there are a lot of introns in human gene. Sometimes, the mutation will cause the difference in surviving abilities of the cell. When these kinds of changes occur, in worst case, the cancer or tumor might be occurred. LITERATURE CITED 1. http://science.jrank.org/pages/4529/Mutagen.htm 2. http://www.microbiologyprocedure.com/gene-mutation/spontaneous-mutations.htm 3. http://www.britannica.com/EBchecked/topic/399695/mutation 4. Brusick, David. Principles of Genetic Toxicology, 2nd ed. New York: Plenum Press, 1987. 5. http://en.wikipedia.org/wiki/Mutagen 6. Lodish H, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipursky SL, Darnell J. (2004). Molecular Biology of the Cell, p963. WH Freeman: New York, NY. 5th ed. 7. http://en.wikipedia.org/wiki/DNA_repair#cite_note-lodish-0 8. John W. Drake, Brian Charlesworth, Deborah Charlesworth, and James F. Crow. Rate of spontaneous mutation. Genetics, Vol. 148, 1667-1686, April 1998, Copyright © 1998