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Tuesday, March 30, 2010

MUTATION ?


Today I learned about Mutation from my Science teacher. Mutation is an interesting science subject indeed.

What is a Mutation ?


1. A mutation is a spontaneous change in a gene or chromosomes, resulting in changes to the characteristic features (phenotype) of the organism.

2. An organism which has genes or chromosomes undergone mutation is called a mutant.

3. Mutations can occur in any cell at anytime, but fortunately mutations seldom happen.

4. Mutations which happen to gametes can cause :

- deformity in the foetus

- damage to the brain

- diseases such as Haemophilia and Down's syndrome.

5. A mutant gene or chromosome can be passed on to future generations.



By Sasbadi Nexus Vista SPM Form 4.5 Science.



Mutation = 突變
Gene = 基因
Chromosomes = 染色體
Deformity in the foetus = 胎兒畸形
Damage to the brain = 大腦損害
Haemophilia = 血友病
Down's syndrome = 唐氏綜合徵


http://ghr.nlm.nih.gov/handbook/illustrations/xlinkrecessivemother

突變在生物學上的含義,是指細胞中的遺傳基因發生的改變。它包括單個鹼基改變所引起的點突變,或多個鹼基的缺失、重複和插入。原因可以是細胞分裂時遺傳基因的複製發生錯誤、或受化學物質、輻射或病毒的影響。
突變通常會導致細胞運作不正常或死亡,甚至可以在較高等生物中引發癌症。但同時,突變也被視為物種進化的「推動力」:不理想的突變會經天擇過程被淘汰,而對物種有利的突變則會被累積下去。中性的突變對物種沒有影響而逐漸累積,會導致間斷平衡。


http://zh.wikipedia.org/zh-hk/%E7%AA%81%E5%8F%98

.....吸煙者平均每吸15支煙,DNA發生1次突變,其中的部分突變會造成基因永久性損傷,甚至患上癌症並可代代相傳.....

http://big5.gov.cn/gate/big5/www.gov.cn/fwxx/kp/2010-03/01/content_1544409.htm

http://mag.epochtimes.com/b5/147/7131.htm

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