a destroyer q

[gomawum]

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one of problem in the destoyer asked

what is promoter site

and it exclude the choices
a)a start site for DNA transcription
c)binding sie for regulatory protein that wil allow for transcription

and included only d) site on DNA at which RNA polymerase binds to iniiate transcription

I thought promoter was a start site for DNA transcription and where transcription factors bind (for eukaroyte) and TaTa box as the sequence in the promoter where RNAP binds..

I don't see why a and c aren't counted which was choice e) more than one of those

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[saltlake007]

What number is this?

 

[nwdmd]

d is right.
http://en.wikipedia.org/wiki/Promoter

 

[gomawum]

I don't get it.
okay I see that trnascription factors are only present in eukaroytes
but why is it not a start stie for DNA transcription?

 

[TheWiredNerv]

Start site is usually the AUG codon.

 

[gomawum]

AUG is start codonfor translatioin.

so what I don't understand is why isn't promoter not start site for transcription since it's where polymerase binds...

 

[nwdmd]

yes, it is the start of transcription, but RNA transcription
not DNA transcription (=wrong answer)

"RNA transcription is initiatied when RNA polymerase binds to promoter in DNA"

tricky answers, google to clarify

 

[smile101]

d is correct because even when polymerase binds to the promoter, there is no guarantee that it will transcribe the DNA. The operator region may have the repressor bind to it, thus blocking the polymerase from moving further!!

Regualtor -->repressor
Promoter--> Polymerase binding site
operator --> repressor binding site
structural region --> transcribing site

look at the campbell book..if visual picture could help you better understand it!

 

[koppa]

a) is not correct, because promoter site is not necessarily the start site of DNA transcription. Some examples include Pribnow box at -10 in prokaryotes and TATA box at -25 in eukaryotes. Start site for DNA transcription is +1.

I think (c) is wrong, because regulatory proteins can either activate or repress transcription. According to (c) regulatory proteins only activate transcription.

 

[smile101]

yes, it is the start of transcription, but RNA transcription
not DNA transcription (=wrong answer)

"RNA transcription is initiatied when RNA polymerase binds to promoter in DNA"

tricky answers, google to clarify

DNA transcription is a process that involves the transcribing of genetic information from DNA to RNA

Its not RNA transcription...its called dna transcription and rna translation