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ChelsM ChelsM
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10 years ago
So, I am having a difficult time with a question. The question and the figure is attached. This is what I think about it so far, but I am really confused and need help.

A) When the preincubation was carried out with the individual templates, Srb2 did show a preference for either template. When the preincubation was carried out with the L template, a band was only seen for the L transcript. On the contrary, when preincubation was carried out with the S template, a band was only seen for the S transcript. However, Srb2 did not show a preference for either template when the preincubation was carried out with the mixture because a band developed for both the L and S transcripts.

B) Stoichiometry deals with the quantitative relationships between the reactants and products in chemical reactions.Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. I am confused because the results do not mention any values and I do not see how the reaction was speed up??? However, I think maybe it might be catalytically because it says "extracts prepared from yeast that are lacking the Srb2 gene cannot transcribe added DNA templates, but they can be activated for transcription by the addition of Srb2 protein."

C) Based on figure B, I believe it may be form part of the preinitiation complex, but I'm not sure and don't know how to explain this.

As you can see, I am really uncertain about this material and do not feel confident with my answers. Also, the answer is supposed to be rather lengthy (1-2 pages) and my answers are very bare bones.
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duddyduddy
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10 years ago
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Here's what you should get:

A) Since an equal amount of transcription from each template was observed when the preincubation was carried out with the individual templates or a mixture (lanes 1 to 3), Srb2 protein does not show a preference for either template.

B) Srb2 acts stoichiometrically. If Srb2 acted catalytically, it should have been able to modify the second template after the two were mixed. Catalytic activity would have produced transcripts from both templates regardless of which one was originally included in the preincubation with Srb2. When excess Srb2 was added at the beginning of the preincubation with one template, transcription was observed from both templates after mixing. This is consistent with a stoichiometric requirement for Srb2 and rules out the possibility that Srb2 was inactivated during the preincubation—and was for that reason unable to act (catalytically) on the second template after mixing.

C) The production of transcripts solely from the template that was preincubated with Srb2 indicates that Srb2 is part of the preinitiation complex. If Srb2 were able to act after transcription had begun, transcripts would have been produced from both templates regardless of which one was included in the preincubation.

Cheers
This verified answer contains over 200 words.
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- Master of Science in Biology
- Bachelor of Science (Biology)
- Bachelor of Education

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wrote...
Educator
10 years ago
Hey ChelsM,

What textbook did you derive these questions from?
wrote...
10 years ago
To duddy: First off thank you, as I wasn't even close. Second, are you getting those answers from a textbook solution manual? The "Here's what you should get:" part makes me think that.

To bio_man: Our class textbook is Molecular Biology of the Cell 5th edition, Alberts et. al, Garland Science. However, these questions are not from our textbook. This was a handout, which I believe may have come from the same textbook, but the 4th edition.
wrote...
Educator
10 years ago
Thanks for the update, ChelsM. Please mark this as solved.
wrote...
Staff Member
10 years ago
Would you like the chapter 6 test-bank solutions to your textbook?

E n j o y Slight Smile
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- Master of Science in Biology
- Bachelor of Science (Biology)
- Bachelor of Education
wrote...
10 years ago
Duddy, thank you so much. Would you also be so kind as to post for this new question attached? I have researched this one and answered it, but I would like to check my answers.
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wrote...
10 years ago
HI|:
I need the test bank of  Molecular Biology of the Cell 5th edition, Alberts et. al, Garland Science. IF any one has it, i Willing to buy it as soon as possible.
wrote...
A month ago
thanks
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