May 22, 2009
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b) A start site for DNA transcription
d) The site on DNA at which RNA polymerase binds to initiate transcription
e) more than one of these

From destroyer 2009, bio 291

I know D is true, but wouldnt b also be true? Therefore making the right answer e or w/e???
 

dentene ice

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hey I also came across the same problem, and i was under the impression that E was the answer too!
 
Jun 14, 2009
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Technically, the promoter region isn't where DNA transcription starts. It begins with the start codon of the transcribed region.
 
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Shinpe
May 22, 2009
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Technically, the promoter region isn't where DNA transcription starts. It begins with the start codon of the transcribed region.
I don't think so. That's true for translation, the ribosome would slide down until it finds AUG, but the transcription of DNA to RNA can start anywhere (well at any promoter region, usually regions that have more AT base-pairing => easier to open the strands). No?
 
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Shinpe
May 22, 2009
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Hmmm actually I don't remember this exactly but does RNA polymerase need an RNA primer too to be able to start transcription or it can do it by itself? Maybe that's the difference? It would have to slide down until it finds a sequence that fits the RNA primer? I really don't remember it being that way though.
 
Jun 14, 2009
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I don't think so. That's true for translation, the ribosome would slide down until it finds AUG, but the transcription of DNA to RNA can start anywhere (well at any promoter region, usually regions that have more AT base-pairing => easier to open the strands). No?
Well, my understanding of it is that promoters are always found upstream of the gene, and are in fact identified by their relative location from the actual transcriptional start site.

i.e. in prokaryotes, the -10 and -35 promoter sequences, which means 10 and 35 base pair upstream of the transcribed region, and in eukaryotes, the TATA box which is located upstream of the transcribed region as well.

*edit*
RNA polymerase doesn't need any priming
 
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Shinpe
May 22, 2009
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Well, my understanding of it is that promoters are always found upstream of the gene, and are in fact identified by their relative location from the actual transcriptional start site.

i.e. in prokaryotes, the -10 and -35 promoter sequences, which means 10 and 35 base pair upstream of the transcribed region, and in eukaryotes, the TATA box which is located upstream of the transcribed region as well.

*edit*
RNA polymerase doesn't need any priming
Now I vaguely remember something like that from mol bio. But I am still pretty sure that transcription doesn't have to get started at the start codon, so do you know what they look for to start transcription after they bind to the promoter region??
 
Jun 14, 2009
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Now I vaguely remember something like that from mol bio. But I am still pretty sure that transcription doesn't have to get started at the start codon, so do you know what they look for to start transcription after they bind to the promoter region??
I don't remember too much about the details, but there was something I recall about RNA polymerase not having the space to transcribe and elongate while it's so close to the transcription initiation complex, but can finally do so once it is sufficiently far away.

My bad on the other thing. Transcription doesn't have to start at a translational start sequence
 
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Shinpe
May 22, 2009
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I don't remember too much about the details, but there was something I recall about RNA polymerase not having the space to transcribe and elongate while it's so close to the transcription initiation complex, but can finally do so once it is sufficiently far away.

My bad on the other thing. Transcription doesn't have to start at a translational start sequence
Sounds familiar. Either way, this is probably enough information for DAT. Thanks.
 
Jun 19, 2009
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b) A start site for DNA transcription
d) The site on DNA at which RNA polymerase binds to initiate transcription
e) more than one of these

From destroyer 2009, bio 291

I know D is true, but wouldnt b also be true? Therefore making the right answer e or w/e???
That is only true for prokaryotes.

Eukaryotic transcription is a lot more complicated. RNA polymerase does not actually bind to the promoter.

General transcription factors, specifically, the DNA binding domain bind to the promoter. The Activation domain of the TF can recruit RNA polymerase, co-activators, etc.

Eukaryotic transcription also involves enhancers which can be located way upstream/downstream from the gene it regulates or in the intronic sequence. Transcription factors that bind to enhancers are called specific transcription factors; they can recruit repressors or co-activators...
 

prsndwg

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Apr 19, 2009
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b) A start site for DNA transcription
d) The site on DNA at which RNA polymerase binds to initiate transcription
e) more than one of these

From destroyer 2009, bio 291

I know D is true, but wouldnt b also be true? Therefore making the right answer e or w/e???
I thought DNA traxpn happens right at the operator site where the enhancer or suppreser binds to it! either enhances it or supresses it..
Polymerase binds to the promoter..
 

Longhorns

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From my understanding the promoter is the binding site of RNA polymerase to initiate transcription, and the start site usually lies upstream ( or downstream?) from the promoter site.
 
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