key_final_winter_2006_mwf

key_final_winter_2006_mwf - lof3 Biological Sciences 102...

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Unformatted text preview: lof3 Biological Sciences 102 Name Last First Winter, 2006 MWF , K. Hilt Final Exam Score (200): pH = PKa + log {[baseJ/[acidn AG = AH - TAS F = (q1 q2)/(s r2) v. = {me [Sn / {Km + [8]} PKa’s of the side chain R-groups are: D (3.9), E (4.2), H (6.0), C (8.3), Y (10.1), K (10.5), and R (12.5). PKa’s of amino acid a-amino group (9.60) and oc-carboxyl group (2.10). PKa’s of N-terminal oligopeptide (1- amino group (7.40) and C-terminal a—carboxyl group (3.6). 1. (15 pts.) A student wants to purchase some trypsin to use in protein sequencing. Company A offers 200 I.U.’s of the enzyme with a specific activity of 405 I.U.lmg at a price of $200. Company B offers 150 I.U.’s of the enzyme with a specific activity of 450 I.U./mg at the same price. Company C offers 405 I.U.’s of the enzyme with a specific activity of 200 I.U.lmg at the same price. Which company(s) should you buy from? a) Company A + g @Company B c) Company C d) Either company A or C e) Either company A or B t) Either company B or C Now briefly explain your answer. Show any necessary calculations. 9.,qu“ sewdnj ¢terM§v¢5 euyg ow*+‘£n3 an (LL va‘fvn . The, quire/5+- eyrpvme. has +144, kiakegl— sq¢oifigya¢+€£ I Le. LDMM») +9 2. (25 pts.) The first workable fraction in enzyme purification is the cruJJL Each subsequent successful purification step should show an increase in 5% of¥ic apt-wig and very little decrease in o idol av en aaH v: . To keep track of all proteins during each step, we would typically run a general protein assay, such as the firuéoval , which utilizes the dye Coomassie Blue, which binds to lag“ dvaelfl glow; groups in proteins. (Fill in e861! line With one or more words). I b ‘Mk + 5, 3. (15 pts.) The pH ofa solution made by mixing 200 ml of0.100 M ammonia with 100 ml of0.10 M HCl is: (a) pH 11.1 H 9.4 (0) pH 5.6 (d) 7.2 (e) 8.1 (t) 6.6 (g) 10.3 Circle the above c osest answer. The Kb of ammonia is 1.8 x 10'5 M. You may use the back of this page for calculations. There is no partial credit. 4. (20 pts.) The net charge, to the nearest 0.01, of the peptide D-E-K-C-R—P at pH 8.10 is —— l . ‘2 2 . Fill in the blank with your answer. You may use the back of this paper for calculations. There is no partial credit. IV -— l . 2 \ 5 3. (o.20v.L)(a.mo M mg) : 0.020 MQ m5 (o.\o-o£,)(o.wv M Hd)2’0,0\0 mwQ H’r 0,0io MOQ U“; ISM are, ‘3— +142 0.010 we NHL? 91‘» o—L MM" "‘13 Kb: [5"‘ID’5 ,III (Kb)<Kar\ '5 [no [44, _ $.55" xlo'm 9K“ 3 67-3; (2.») LI‘ gp—D—E- K—c—Q—P-cme who) g 8 § 4 GD 0/- — 7( L543) 7" V \+— K +\ <33?) wo: $3 +1 Z a”? 0.20:1”? p”=f“‘v*"3’:: L3: 9% w b: is}: 0.387 ?-' 37H0+|a¢ka l WW \1 "c :@ 0'7 2 a, _. \ - 22L: b; 0" g. m ’ L.” cad—rah = G 0.1%) +(-o.3s¢\+(—c\ :. —I.121 p. 2of3 BIS 102 Name Q 5. (20 pts.) The number of moles of HCl required to lower the pH of 600 ml of 0.300 M glycine bufier, pH 9.80 to a final pH of 2.40 is: 0, I '7 moles. You may use the back of this paper for calculations. There is no partial credit. ' | 6. (10 pts.) The following amino acid sequence is most likely to be in an or-helix at pH ’2’: a) W-Y-A—F—W—V-V-L-L D-D-D-D-D-D-D-D-D V-S-S-M-A-V-L-L—L d) T-K-K—H-H—L-L-V-V e) F-A—P-T-Y-D-M-W—A f) T—Y-G—G-E-K—F—A-V Circle the above best answer. 7. (10 pts.) Afier many purification steps, the enzyme Z solution that you have yields the following analytical results: 3 bands on a SDS-PAGE gel 1 band on an IEF gel 1 band on a native PAGE gel You should correctly conclude that the enzyme Z solution is: probably pure based on all three gel results ) probably impure based on all three gel results Circle the above best answer. 8. (20 pts.) A Lineweaver—Burk plot was made of an enzyme catalyzed reaction both in the presence and absence of reversible inhibitor “1”. What was observed was a(an) i norm: 2. in Kin and no okamq e. in Vmax , as “I” turned out to be a competitive inhibitor. If the kinetic experiments had been re-done using half as much enzyme in every reaction (test tube), then Vmax would be had 5? the original vmax and Km would be unok M? at . (Fill in each blank with one or more words). 4— 5' wok blmd’. 9. (15 pts.) The balanced chemical reaction for the reaction of cystine with excess mercaptoethanol at pH 7 is (use chemical structures for all compounds): a ms” cw— — + r _ .t I aim 0°") ' H 9“ 9" Pl} F] ’f‘ H l-l lo M *— u5-¢flz¢HI-OH —¢-_—§ Z u+,.)-\c‘-'H + s‘ G L z "*2 Ml:— 3 one s —-¢u,, cur 0* L 5 — 5 “A 4. l \ s H 4— 3 4— 5 + 5, MW “3 (WW/L “3 (4545M 2.57 " 5k?! dam = C0.6\2)(0.|8=wu-Q 3‘33 7 @H: Qua, + 240= 2.! + I .3: __ in} a 30— If} a. a. , ~ T .. I _ a- .3. ,_ 0.333 54—“, 2 Jam —. Cb.333)(a.t& m4. aha) 1" 0- 05‘7"? Mh‘e "'4‘ (gird H“ mafi new = 0.0%? »« a.“ c o./é‘f‘7 3of3 BIS 102 Name 14% 10. (10 pts.) An increase in the fluidity of animal membranes is made possible by: a) decreasing the length of fatty acid components b) increasing the number of cis double bonds 0 increasing the concentration of cholesterol aandb e) b and c i) all of the above Circle the letter of the above best answer. 11. (10 pts.) In the catalytic triad of chymotrypsin, a pH of 4 will seriously impair the function of which . L 5 resume? WhY? Hi’hx"; T" “‘1 “5 " 5933M. +t... wsmune mus-r \oe wwtro+om+eA. FH— Q“ q. H. Wm be, prod-uncred. +3 12. (15 pts.) An internal peptide of a protein was obtained by treating the intact protein with Asp-N. Amino acid analysis of the internal peptide gave 1 mol of R, Y, and D; but 2 mols each of C and K. Treatment of the intact peptide with trypsin gave a dipeptide of K and C; a tripeptide of K, C, and D; free Y; and free R. The sequence of the original internal peptide is: cK or cK RCKY +5 i4- ’1 t ’t T f t saws . ‘ W we“ o‘eever- evs?‘~‘"“j“’ *$ 13. (15 pts.) The following table lists properties of four different proteins: . [- oolwmn I: MSaA‘woL-a Jam) v a) What is the order of elution from a cation exchange column at pH 7? (first) ovkibumln H9 ck Mo‘\‘r s'mn rx \ at e. b) What is the order of migration of the above proteins in a SDS-PAGE gel? (fastest) I 507, Hb Swlrum'l's 0"» mm [u oval uw‘ (slowest) c) What is the order of elution of the above proteins from a sizing column at pH 7? (first) Hb ova.\lmumiu wrh sh.» an 501' (last) D—(R‘V)c’ C)K)\¢3 i ‘\'V‘3€$\‘v\ V b—c-K—c—KLR‘LY DY‘ A. & 3, baa-K—R—c- K-H’ ...
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key_final_winter_2006_mwf - lof3 Biological Sciences 102...

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