MidTermPracProb

MidTermPracProb - Chemistry 114A (Midterm Practice Problem...

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Chemistry 114A (Midterm Practice Problem Set): Fall 2007 1. The pKa of the amino group in alanine is 9.62. In a solution at pH 8.62, what fraction of the amino groups is unprotonated? A. 0.045, B. 0.09, C. 0.l35, D. 0.l8, E. 0.225 2) A protein has a molecular weight of l60,000. Roughly how many amino acid residues ( average MW of an amino acid is 110) does it contain? A. 1,000, B. 1,200, C. 1,400, D. 1,600, E. 1,800 3) In a solution of pH 1 A. lysine will be more negatively charged than glutamic acid. B. lysine will be more positively charged than glutamic acid. C. lysine and glutamic acid will carry the same net charge. D. none of the above 4. What is the isoelectric point of cysteine? (pK1 = 1.96, pK2 = 8.18 and pK3 = 10.28)? A. 1.96, B. 5.07, C. 8.18, D. 9.23, E. 10.28 5. Over what approximate pH ranges would glutamic acid exhibit significant buffering activities? A. Only 5 to 8.5, B. Only 3 to 5, C. Only 8.5 to 10.5, D. Only 1 to 3 and 8.5 to 10.5, E. Only 1 to 5 and 8.5 to 10.5 6. Which of the following amino acids can buffer most effectively at physiological pH? A. Glycine, B. Histidine, C. Arginine, D. Phenylalanine, E. Aspartate 7. Which amino acid contains a sulfur atom? A. Arginine, B. Aspartate, C. Methionine, D. Leucine, E. Serine 8. How many peptides or free amino acids would result from treatment of the following peptide with trypsin? Met-Gly-Lys-Ala-Leu-Arg-Gly-Ser
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A. 2, B. 3, C. 4, D. 5 9. Edman degradation refers to A. a metabolic pathway for catabolism of proteins. B. a chemical method for determination of the N-terminal amino acid sequence of proteins and polypeptides. C. an enzymatic method for determination of the C-terminal sequence of proteins and polypeptides. D.
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This note was uploaded on 10/28/2010 for the course CHEM 114A taught by Professor Viadhiu during the Fall '08 term at UCSD.

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MidTermPracProb - Chemistry 114A (Midterm Practice Problem...

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