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TUID#39 The following diagram is a model of theribonuclease molecule. The structure indicated bynumber 1 on the diagram is.

a. a ringb. a random coilc. an alpha helix

beta pleated sheete. all of the above

(Do NOT write your name)

40. Consider a microscope slide with the following cell on it. Assume that the dimensions of thed rent structures are as follows (the drawing is not exactly to scale. :

0 microns I 0 10 U (.) n Y'\ 2. 4 microns wide and 3 microns across 1.-f OVO X 50VO A fn../). 2 microns diameter ..,.. W {)U Y\ fY\.A. 3 microns long and 0.4 microns across 3 L)t )Q X 4 () tJ Y\ fV\

5. 0.2 microns in diameter 200 V't """'Which structure(s) would you expect to see if the numerical aperture was 1, and the light wasmonochromatic with a wavelength of 500 nm. Note: I micron = I 000 nm .

Glo soo'a. I,2,3,4,5

6)1,2,3,4,c. I,2,3,d. I,2e. I

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TUID# (Do NOT write your name)35. Imagine that you have...tb.ree enzymes. ~ n z y m e (a.) has a Km Q.tQJjJ] Enzyme (b) has a KQo.lJEnzyme (c) has f1J.o) All are i_!lJ!-M If you wanted to conserve s u b s t r ~ t e , a n d ~ ~ J i l i e - < " ;:::::unt hat would stilljjive which would you choose? -

Y.'Enzyme bc. Enzyme c 1 -d. Any of them, because Km has nothing ~ ~ ~ 1e. Can't choose. It depends on the V max36. The Km of a reaction is all of the following except:~ ~ a s u r e of the affinity of the enzyme for the substrate under some conditions.vb.>measure of the substrate concentration needed to drive the reaction at half of its maximum rate.kinetic value that can be determined from Lineweaver-Burk plots of enzyme velocities.

d. the combined result of the rate constants for the forward and back reactions of an enzyme reactionhalfof Vmax

37. One can consider chromatography to result from competition for the sample by two components ofthe system. These two are:.)l0Jravity and the MatrixXGravity and the Liquid Phase/ ; ) Liquid phase and the matrix'c( Liquid phase and the samplee. Sample and the matrix

38. Sodium dodecyl sulfate (SDS., used in Polyacrylamide Gel Electrophoresis, has all of the followingproperties except:binds to the backbone of protein molecules.Jl It breaks hydrogen bonds.{c) It breaks disulfide bonds.

~ c a u s e s proteins to unfold into essentially linear molecules.~ p p l i e s a charge proportional to the size of the protein to which it binds.

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TUID# (Do NOT write your name)3I . Which of these amino acids causes a kink in the primary structure of a protein?a. leucineb. argininec. aspartic acid

() p r o l i ~ e e. cysteme32. Let's say that you wanted to investigate the ability of a small protein to recover after it has beendenatured. You denature the protein with urea and beta-mercaptoethanol (bme. , and then try to renaturethe protein with the following procedures:I. remove the urea and leave the bme in the sol.ution.2. r e m o ~ e the bme and leave the urea in the solution. ,.--3. remove both at once. 4. first remove the u r e a ~ and then remove the bme. < ; ; ~ \....A.s-c..r {L .5. first remove the bme and then remove the urea.You obtain the following results from your experiment:

Procedure ResultI No activity restored2 No activity restored3 No activity restored4 No activity restored5 No activitv restored

OMG! Which of the following tentative conclusions would NOT be valid from this experiment?a. the bme had no effe9t. ' b. the bme was inactivec_a_.nit- ( ) S ~ ()the amino acid sequence of the protein was sufficient for it to resume its configuration.+VU"'

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TUID# (Do NOT write your name)26. Imagine that you have a protein mixture containing two proteins. The first is a monmeric protein,and the second is a dimer of two identis! subunits. The molecular weight of the first is 40,000, and themolecular weight of the second is 80,000. g

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TUID# -- -- -- -- -- -- -- --(Do NOT write your name)21. Which of the following is NOT true for flu

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TUID# (Do NOT write your name)16. What is the important characteristic of the ~ ~ o r ~ t h a t makes phase contrastmicroscopy possible? ,____ ~ I s have different refractive index, which cause differences in light phase shifting and

),e{h changes.b. Different materials tum light that pass through it into different color by changing its wavelengths./ The specimen has its own 30 shape, which would reflects Itself clearly under the microscope r o i f f e r en t proteins absorb the dye differently, which make the contrast under the microscopy clearer.e. None of the above.

17. Imagine that you have a solution whose r e f r a c t i ~ d e x . . e x a c t ~ matches that of cellular components.If you prepared a microscope slide with unstained cells and used this solution as a mounting medium,which cellular structures would you be able to see with a phase contrast microscope?a. Membranesb. Vesiclesc. the nucleusd. a brush border{) nothing.18. In what order does the light from a microscope pass through the lenses necessary to create amagnified, real image of a specimen?a. objective lens, condenser lens, ocular lens, eye lensb, condenser lens, objective lens, eye lens, ocular lensc. objective lens, condenser lens, eye lens, ocular lens@ o n d e n ~ e r lens, objective lens, ocular lens, eye lense. ocular lens, objective lens, condenser lens, eye lensI9. The electron microscope has greater resolution than the light microscope becausea. wavelength of electron is equal to that of visible light

@wavelength of electron is smaller than that of visible light'c. wavelength of electron is greater than that of visible lightd. it does not 'kill' the samplee. the image is formed by f o c ~ s i n g on a fluorescent screen20. The standard method of examining cells with a microscope requires fixation of cells, often withaldehydes such as formaldehyde . What is the effect of fixatism? -

yattachment of fluorescent molecule to a protein of interest that has specific binding capabilitiesb. Greater resolution of the imagec. staining of cells so that the organelles are easy to identify

(!}recipitation and cross inking of proteins .e. removal of lipid components - ~ ' \ \ . _ _ ( dJ o.:h l) V')

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TUID# (Do NOT write your name)I0. Which of these groups are found in all amino acids?/ ..,.- ..,.,.. _,.

Amino; c a ~ b o ~ l , a hydrogen and R groupb. R group, ~ y l , a hydrogen and phosphatec. P h o ~ e , s ~ y d r y l , amino, carbonyld. Amino, hydrogen, a ~ e e. A l ~ o l , amino, R group, a hydrogen11. All of the following are examples ofHydrophobic substances except:~ a l i n e { ) A r g i n i n e ~ ~ i t . . ~ M e t h a n e ~ s o leucineyrryptophane

cuCIJI\tA..i-\lOl \ \.J.:..; .\ eu.tC.. I()..(..,f ~ O t ~ L I U -tvy ~ ' 1 ' 7 ( - \ . 0 U )

tl}'\...l.Ji1 \uY\'vQcJatvltYL.(_ .f!.U1tru_S\Y (:A(\L12. You are close to developing a novel protein that enhances muscle synthesis in athletes. However,you need to shorten its structure for better absorption an etter results. You need to take out twoof the amino acids and make the overall protein m o n ~ dro hilic. What two amino acids would y o ~ take out to best achieve this needed effect?---a ) ~ a n d G l y c i n e fJOlQY' ~ ~ v t t _ ~ < ; t ' l . f N - -b ~ a n d Tyrosine .:.fh.Q{oSL J1-L c ) c ; y c i n e a n d ~ ~ ~ J Y L J L _l_AAlanine a n d ~ , ( _~ e u c i n e and Phenylalanine ' } _ ~ ~ Y U . ~ ~ . 1 1 ~ ' 13. Molecules, such as fatty acids, that have both hydrophobic and hydrgphilic regions are said to be ....a. ionicb. saturated~ u n s a t u r a t e d vamphipathice. magnetic14. Which of the following colored substances could be used as a stain that would yield the best imageof goblet cells when viewed with a microscope?a. HematoxylinX Chlorophyllc. Green Fluorescent Protein~ E o s i n jY. Hemoglobin15. The phase contrast microscope does all of the following except:a. Makes highly transparent objects more visible / ~ 1 { U . J r@ Converts differences in refractive index into differences i n , ~ _ . . . . . . . . . . c. Separates the direct light entering the objective lens from t h ~ d light _.....,.d. Takes advantage ofthe interference of l i gh t - - - -) All of the above are true

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TUID# (Do NOT write your name)5. During gel filtration chromatography, a mixture of 3 proteins of similar shape, that are 2SO kDa,60kDa, and 150kDa are passed through a column of Sephadex G-150 beads. The beads allow entry ofproteins that are about 2QO kDa. In what order, going from left to right, do the proteins filter out of the~ ~ ~ z:p,\to,. The 250kDa protein first, second the 60kDa protein, and lastly the 150kDa protein.b. The 60kDa protein first, the 150kDa protein second, and lastly the 250kDa protein.kJrhe 250kDa protein first, the 150kDa protein second, and lastly the 60kDa protein.d.The 150kDa protein first, 250kDa protein second, and lastly the 60kDa protein.e. The 60kDa protein first, the 250KDa protein second, and lastly the 150kDa protein.6. Which free amino acid has the greatest amount of negative charge at pH 6.2?a. Arginine with an pi of 10.76 k : : : > ~ S.t -c:_b. Serine with an pi of 5.68

--rc)Aspartate with an pi of 2.77-"'(( asparagine with an pi of 5.41e. cysteine with an pi of5.07 1 . - o ~ S i r - L

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7. Which of the following is NOT a characteristic exploited in separation ofmaterials?a. Sizeb. Shape(C:}.Reactivityd. Chargee. Affinity8. Dr. Seuss wanted to know the relative sizes of three newly discovered proteins with the same pH andcharge, named Thingl, Thing2, and Thing3. Therefore, he set up a gel filtration column. Thing3 elJ.!tedfirst and Thingl and Thing2 came out together next. Can you determine the relative sizes of the proteins,because Dr. Seuss is very perplexed? 3 / ( \ -::: '2...")a. (Thingl=Thing2)>Thing3b. Depends if the column is right side up or not

tf)Thingl=Thing2)

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TUID# (Do NOT write your name)I. You wish to purity an enzyme and determine its activity. You know that the protein contains theamino acid sequence G)y, Trp, Asp, Ser, Lys, Arg. You start with several different samples, and youdiscover that each one has a different mutation in the amino acid sequence. You decide to carry on withthe analysis in hopes that one of them will have at least s o m ~ activity. Which of the following fivesequences would you expect to give you the best result?

. . ~ n P p 0 _ & -a. Gly,Tyr,Asp,Ser,Lys,Arg \ ' - / ~ I f ~ ~ b. Asp, Trp, Asp, Ser, Lys, Arg - S flu.. fc. Gly, Trp, Asp, Ser, Asp, Arg ..: . ~ . , f ? r ~ J . . -thf"mu G)_\'(,d. Gly, Trp, Asp, Thr, Lys, Arg L-e.ut . 'A( ; ~ y , M e t , ~ , T h r , L y s , A r g ~ e t j 2. In Centrifugation, which of the following does not affect the movement of the sample?a. Size of the objectb. Shape of the objectc. Density of the medium.d. The charge of the objectG)Density of the object 3. You are trying to improve the separation oftwo proteins that appear simultaneously in the excludedvolu!Jle o( a gel filtration column. Their molecular masses are 1.8 X 105 daltons and 2.0 X I05 daltons.How can you improve the separation?

Use a gel with smaller poresUse a gel with larger poresReduce the volume of the sampleDecrease the length of the columnIncrease the volume of the sample

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4. Which ofthe following is not a determining factor in the relative movement of proteins through apolyacrylamide gel in PAGE fractionation?

Aha r ge densityb. shape/ s i ze,K.'the concentration of acrylamide present in the gel@he wavelength of light that the protein absorbs

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TUID#3- '_L _2_ _Q_ 4 $.-- 2 IL(Do NOT write your name)

. 1 - ~ - - . . . . . , . . . . . . . _ ' * " " ' " ' T , ' I I I l i ' P : - - _ . . - . . . . . _ _ . . , , ) Y ~ c \ i o i i ! _ ._ __..;:Cf .Ln ~ / e : r m ' n ~ hodbea&t7 lA.r b i o c ~ ; g - .

Biology 3096 First Hour ExaminationTHIS IS TEST CODE 11

October 4, 2010Enter your TUID at the upper right of this page.

Return this exam when you are finished

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