key midterm 2 fall 2007

key midterm 2 fall 2007 - BIS 102 Name 15% Fall, 2007 Last...

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Unformatted text preview: BIS 102 Name 15% Fall, 2007 Last First K. Hilt Second Midterm Score (100): Equations: pH = pK, + log {[b]/[a]} Ka = 2/(y-x) Kb = x2/ (y-x) pH = (pKal + pKa2)/2 (K,)(K.,) = 1 x 10‘14 F=(q1q2)/t-:12 AG=AH-TAS Amino acid pKa’s: a-carboxyl group (2.1), oc-amino group (9.6) side chains: D (3.9) E (4.2) H (6.0) C (8.3) Y (10.1) Oligopeptide pKa’s: C-terminal carboxyl group (3.6), N-terminal amino group (7.4) K (10.5) R (12.5) 1. (20 pts.) Amino acid analysis of protein “Z” gave the following experimental results: What is the net charge (to the nearest 0.01) of protein “Z” at pH 9.4? Put your answer on the following line: 1") . 5' z. . To receive credit, you must show all of your work on the back of this page. 2. (30 ts.) Fill in the followin table, concerning these allosteric effectors of Hb: Effector Positive or Binding Site(s) Strengthen, Create, and/or Ne ative? Break Salt Brides? + _ + BPG *2- - mm was mm Cl- ‘ i +2. " +\ (Jail + cx *1 -m AM +2 6“ " “’W’“ evil C- lam. 514— m fi'SuFum' mfl n-W. cm. oC-swvaoi'I-ls swam *2 3. (10 pts. Some organisms do not use BPG as an allosteric effector of Hb. Instead, they use (circle the best answer) w. glucose, c) arginine, or d) valine. Now defend your choice using just the lines provided: +3 +3 +7. ATP +n‘va c0. +5 brmfl +0 m 4 4—; pail-I‘ve ckggjreg an «AA fi'skbccni‘i'. . 1+? )2 A: lof2 20f2 BIS 102 Name ____\é:9________ 4. (10 pts.) How many moles of 02 will be released if a liter of blood containing 50 g of hemoglobin is transferred from 30 torr, pH 7.6 to 10 torr, pH 7.2? Hemoglobin has a molecular weight of 68,000. Show all calculations. 50 '9 .. 7 -HHWQ [-H, 57, am 31M '3 i {1361-15qu12 HMO—OCO-s‘SB: 2.5xto we 02 ' % 02 Bound — A4 3’ releM ‘= 11$!qu —- 2. 6'1 l)0 msQ = 22.31»! n'" moé oz ‘reieaseoq 5. (5 pts.) Which of the following sequences is most likely to be involved in a oc-helix? Circle your answer. a) D-fi’mF-V-A b) D-K-ECD-F c) LaP‘M-F-A e) aandc 6. (10 pts.) A protein was completely digested with asp-N and an internal peptide (i.e. not derived from the N— or C-terminals) was purified. Determine its sequence from the following information: a) amino acid analysis yields one mole of L, M, W, T, Y, D, and K per mole of peptide; b) treatment of the intact peptide with carboxypeptidase A and B yields threonine; c) treatment of the intact peptide with chymotrypsin yields free tyrosine; a tripeptide containing methionine, threonine, and leucine; and a tripeptide containing lysine, tryptophan, and aspartic acid; d) treatment of the original intact peptide With cyanogen bromide gives a free amino acid and a hexapeptide. +\ + \ H +\ +\ n +\ The sequence of the original peptide is (use the one-letter codes): 5; - E - L0 —— ffl ’- L - H -T . , a + 3 i «f- o.\\ ochre cf 7. (5 pts.) What was Dr. Levinthal’s contribution to the topic of “protein folding”? Confine your answer to justtheselines: _P«Dj& High—ma is via?“ a. rambm Walk. 8. (5 pts.) The main conclusion drawn from a Ramachandran plot is what? Confme your answer to just these lines: a. re. {7 .‘ ce in a. r . 9. (5 pts.) Which is more stable: an a-helix made up of 10 a.a. residues or a parallel fi-pleated sheet consisting of two strands of 5 a.a. residues each? Explain. Confine your answer to just these lines: + z oL- LL13; +.I IO r¢SFM will “(arm n—‘f = b H‘bwo‘a. TLc. W ~: A m be fist An. ml t' _ ~e u rm 3 am on ...
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This test prep was uploaded on 04/21/2008 for the course BIS 102 taught by Professor Hilt during the Spring '08 term at UC Davis.

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key midterm 2 fall 2007 - BIS 102 Name 15% Fall, 2007 Last...

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