UMD BCHM 461 - Exam1_2012 (7 pages)

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Exam1_2012



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Exam1_2012

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Pages:
7
School:
University of Maryland, College Park
Course:
Bchm 461 - Biochemistry I
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BCHM 461 0101 Name 1 October 16 2012 Dr Paul Paukstelis Exam 1 Score 1 30 2 60 3 60 4 50 Total 200 Exams written in pencil or erasable ink will NOT be re graded under any circumstances The University of Maryland Honor Pledge The Honor Pledge is a statement that University of Maryland students are required to write out and sign on examinations The Pledge reads I pledge on my honor that I have not given or received any unauthorized assistance on this examination After you have completed this examination please hand write this pledge into the box below followed by your signature BCHM 461 0101 October 16 2012 Dr Paul Paukstelis Name 2 Exam 1 200 points 1 30 points Bioenergetics A process is observed to be spontaneous with the value of H for this process greater than 0 A 10 points What general conclusions can you draw about the values of S G and H What drives this process B 8 points Describe a likely scenario if the temperature under which this process is observed is decreased Be specific C 6 points Write down the formula you used to come to conclusions in the above questions D 6 points Describe two ways we can drive a simple reaction A forward direction B C in the BCHM 461 0101 October 16 2012 Dr Paul Paukstelis Name 3 3 60 points Nucleic Acids A 20 points Beginning with the partial image below draw a second RNA nucleotide through a standard 5 3 phosphodiester linkage As part of your drawing In the box provided draw an adenine nucleobase connected through a standard glyosidic linkage B 12 points On the image above draw the mechanism for alkaline hydrolysis of RNA Use arrows for electrons pushing Identify the nucleophile what is activating the nucleophile and the intermediate D 12 points BCHM 461 0101 Name 4 October 16 2012 Dr Paul Paukstelis E 4 60 points Peptide Chemistry and Chemical Structure You are working with a peptide of 14 residues GRTLLKNTAYAKWR A 30 points You digest this peptide using the endopeptidase trypsin How many peptides will you have after complete digestion Draw the complete chemical structure of th e peptide with the most residues following the digestion B 6 points On the chemical structure you drew above clearly identify the ionizable functional groups present in the peptide C 12 points You now completely digest the starting peptide with chymotrypsin trypsin and cyanogen bromide together Using one letter abbreviations write down all of the peptides resulting from this digestion BCHM 461 0101 October 16 2012 Dr Paul Paukstelis Name 5 D 12 points Based on the digest performed in Part C identify the least basic peptide Briefly explain why you chose this peptide and estimate its pI 5 50 points Think it through You are given six solutions A B C D E and F Each of the solutions contains the following molecules Mol1 5 ATGGATCCAGA 3 and 5 TCTGGATCCAT 3 Mol2 5 ATGGGCTCAGGA 3 and 5 TCCTGAGCCCAT 3 Mol3 5 ATGGATCCAGA 3 and 5 TCTGGATCCAT 3 and 6M Urea a chaotropic agent Mol4 Asp Glu Lys Lys Thr Cys Ile Leu Leu Mol5 Asp Glu Lys Lys Thr Cys Ile Leu Leu and DTT a reducing agent Mol6 W H Y F I N G F I R E A L A R M You acquire or are given the following experimental data for the six solutions Solution A absorbance maximum at 260 nm with A260 1 0 Solution B absorbance maximum at 280 nm with 280 M 1 cm 1 6970 Solution C absorbance maximum at 260 nm A260 0 5 Tm 38 C Solution D no absorbance in the 250 290 nm range Solution E absorbance maximum at 280 nm with 280 M 1 cm 1 120 Solution F absorbance maximum at 260 nm and Tm 30 C Below assign each molecule to a solution Each molecule can only be assigned once In the space provided you must briefly justify your answer by identifying how chemical moieties and or physical properties of the molecule you assign fit the data A 10 points Mol1 is assigned to B 10 points Mol2is assigned to C 10 points Mol3 is assigned to D 8 points Mol4 is assigned to BCHM 461 0101 October 16 2012 Dr Paul Paukstelis E 6 points Mol5 is assigned to F 6 points Mol6 is assigned to Name 6 BCHM 461 0101 October 16 2012 Dr Paul Paukstelis Name 7 THIS IS A SCRATCH PAGE FOR CALCULATIONS DO NOT INCLUDE OR REFERENCE ANSWERS TO THIS PAGE THE VERY FIRST THING I AM GOING TO DO IS TEAR THIS PAGE OFF AND THROW IT IN A RECYLING BIN


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