生物技術概論~何謂非編碼DNA?

[匿名]

2008-10-08 6:59 am

何謂非編碼DNA?

(A)外顯子

(B)不會產生mRNA的DNA

(C)沒有含氮鹼基的DNA

(D)沒有磷酸的DNA

麻煩幫我詳細說明非編碼DNA的特性

以及為何如(B)所說?

我選(B)沒錯吧!

回答 (2)

[匿名]

2008-10-08 11:19 pm

✔ 最佳答案

非編碼DNA is non-coding DNA. Basically, when a segment of DNA is first expressed, the RNA product are divided into exons and introns. Introns are then spliced and only the exons make up the mRNA that is then translated into protein. In general, coding DNA refers to exons or DNA that encodes other functional entities such as miRNA or rRNA. Non-coding DNA refers to everything else. So...

(A)外顯子 (exon)
As explained above, they are CODING DNA.

(B)不會產生mRNA的DNA
This includes BOTH intronic DNA and intergenic DNA (for example, DNA in between genes). These are NON-CODING DNA.

(C)沒有含氮鹼基的DNA
I think this is just to throw you off... DNA with no base is .... not really a DNA.

(D)沒有磷酸的DNA
This is similar to C.... DNA with no PO4 terminal is not really DNA either...

So... let's emphasize this -
any DNA that becomes part of the mRNA (for the most part) is CODING-DNA.
anything else is NON-CODING DNA. But Non-coding DNA does not mean it is junk DNA or unimportant. Keep that in mind.

參考: I'm a graduate student in Genetics

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馬克

2008-10-08 6:44 pm

B!因為真核細胞的DNA中間會有一些轉錄後(前mRNA)會切除的段落!一般稱為"內插子"!
應該就是你說的"非編碼DNA"!

2008-10-09 11:02:08 補充：
非編碼DNA除了上述之外，應該還包括不用轉錄的DNA!

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