gene expression

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gene expression

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drpkaur
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09/11/06 - 09:36 PM

Which of the following is TRUE for human gene expression?
A. Enhancers only work when they are in close proximity to the promoter.

B. The promoters of actively regulated genes often lack the TATA box

C. CG islands near housekeeping genes are heavily methylated.

D. Enhancers may be located downstream of the genes which they regulate.

E. Enhancers act by inhibiting termination of transcription in eukaryotic genes

vanshita
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09/11/06 - 09:39 PM

blueocean
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09/12/06 - 06:13 AM

docsrinu
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09/13/06 - 09:40 AM

what is the ans?

Ivil
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09/13/06 - 11:34 AM

D is the ans

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drpkaur
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09/13/06 - 11:47 AM

Answer D.
Depending on the gene involved, enhancers can be either upstream or downstream.

A. Enhancers can be effective when they are 1000 base pairs away from the promoter.

B. Actively regulated genes require an AT rich sequence, known as the TATA box, presumably to facilitate local melting of the DNA for efficient binding of RNA polymerase.

C. In contrast to other locations in the genome, CG islands, which are repetitive sequences of several thousand (CG)n pairs, are unmethylated in the upstream region of housekeeping genes.

E. Enhancers act by stimulating the initiation of transcription in genes.

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