Midterm 2a - CHEM114C Midterm II Name _ May 18, 2010 ID#_...

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CHEM114C Name ______________________________ Midterm II May 18, 2010 ID#________________________________ Please write your name on each page. Your exam should have 5 pages including this cover page, with a total of 4 questions. Be certain that all work you want graded is written in permanent ink. You can use the back of the page to continue your answer. Do not use a calculator. This exam is 60 min long – work swiftly, most answers are short. GOOD LUCK! Your score 1. (30)_________ 2. (30)_________ 3. (30)_________ 4. (30)_________ Total (120)______________ This midterm counts 25% towards your final grade in this course. -5-
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CHEM114C Name ______________________________ Midterm II 1. Transcription is carried out by RNA polymerases. (30 total) 1.a) What is the subunit structure of the elongating E.coli RNA polymerase and which ion is located in the active site? (4) Subunits -alpha -beta -beta prime (NO SIGMA!!!!) REMEMBER!! embedded ions - Zn 2+ , Mg2+ 1.b) Write down the polymerization reaction that is catalyzed by this enzyme. (4) (RNA)n + NTP ---> (RNA)+ PPi , PPi + H20 ---> 2Pi 1.c) Diagram (on backpage) the transcription bubble indicating the directionality of sense and anti-sense DNA strands and the nascent RNA. (4) 5’ ________________------------------______________________3’ Sense 5’-----------------3’ (Nascent RNA) 3’--------------------------___________-----------------------------------5’ Antisense +1 Nascent RNA? 1.d) Name the two footprinting techniques that reveal how the RNA polymerase interacts with the template? What do they tell us, and how do they work? (use the backpage) (6) DNAse 1 Footing Printing Tell: Location where the protein binds because thee enzyme can access the DNA when it binds) How: Use denaturing solution to turn dsdna into ssdna. Have the DNA strand labeled. ( Why does it need to be labeled?)Use a general DNASE that nick randomly (NOT SPECIFICALLY) the ssDNA. Run through the gel electrophoresis. Shorter strand will go on the bottom while longer strand goes on the top. Certain length couldn’t be obtained due to the probability that protein binds to that DNA at that location Dmethylsulfate (DMS) Footprinting Tell: protections of DNA and enhancement of. ..?? reveal where protein is bound but in addition DMA where the DNA is distored or single strand as the ssdna is more prone to -5-
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CHEM114C Name ______________________________ Midterm II methylation methylated gunaine is prone to cleavage. .. the place where protein binds will How: 1.Label DNA fragment. 2. Bind Protein to DNA.
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This note was uploaded on 05/27/2011 for the course CHEM 114B chem 114B taught by Professor Weng during the Winter '11 term at UCSD.

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Midterm 2a - CHEM114C Midterm II Name _ May 18, 2010 ID#_...

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