midterm_1_key

midterm_1_key - Last Name: _ First Name: _ Lab (day and...

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Last Name : _______________________________ First Name : ______________________ 1 BISC 320 - Midterm 1 (100 pts) Fall, 2005 Multiple choice questions are worth 3 points each. Choose the BEST answer for each. 1. The structure of an alpha-helix may be: a) amphipathic b) held together by disulfide bonds c) contain a proline every 7 th amino acid d) all of the above 2. When two atoms differing in electronegativity are joined in a covalent bond, then: a) the electrons are shared equally between the atoms b) the bond is nonpolar c) the atom with the greater electronegativity attracts the bonded electrons more d) a double bond is formed 3. (4 pts.) Name two reasons sodium dodecyl sulfate (SDS) is used in denaturing gel electrophoresis of proteins. Give one of these answers in terms of the mass to charge ratio of the proteins. 1) it denatures the secondary and tertiary structure of the protein so that differences in the native conformations of proteins do not affect migration in the gel 2) it equalizes the mass to charge ratio of all proteins so they all move at an equal rate in the electric field (thus the rate of movement depends only on the mass of the proteins) 4. (3 pts.) Why do many DNA binding proteins bind palindromic sequences? They bind as dimers, where each monomer recognizes half of the sequence 5. (3pts.) Name three amino acids that may be phosphorylated. Serine, threonine, tyrosine 6. ( 4 pts.) How did Avery, McCleod, and McCarty define the “transforming principle” first identified by Griffiths? 1) they fractionated the bacterial extract into chemical constituents of protein, DNA, carbohydrates 2) the then used DNAse to show that it was in fact the DNA in the DNA fraction that caused transformation Lab (day and time): _____________________________ TAs: ___________________________
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Last Name : _______________________________ First Name : ______________________ 2 Multiple choice questions are worth 3 points each. Choose the BEST answer for each. 7. Which of the following dsDNA sequences (only one strand shown) appears to contain a consensus-
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This note was uploaded on 09/17/2009 for the course BISC 320L taught by Professor Baker,aparicio during the Fall '07 term at USC.

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midterm_1_key - Last Name: _ First Name: _ Lab (day and...

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