F06_exam_1_v1 - 09:25 FAX 512 471 6135 BIOCHEM DIV —>...

Info icon This preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 09/26/2006 09:25 FAX 512 471 6135 BIOCHEM DIV —> ELECTR RESERVE .001 CH 369 Exam 1 September 21. 2006 Namc: i ; {1% cm — I. (10 pts) Match the following: Use the BEST answer. one amino acid may fit two descriptions. but one description is either unique or better! 1. Polar €1- Wynn-1mm 2. ‘IBEIsic H fi—proiine 3. Contains Sulfur b WW 4. Smallest side chain (R group) 3 494m 5. Non-polar 0,. mm 6. Contains a hydroxy] group 5, WE. 7. Often found at turns or ends of alpha-helix in proteinsE) W s, Acidic F Wine 9. Aromatic fl - Ai-cysteino 10. Affected by oxidetionlruduotion I v—Jfi—giyoi-ne— II. (4 p115) Match the following structures to the correct name. a. methionine b. cysteine c. serine d. threonine c. glutamine f. a5paragine g.vaiinc ILIeucine i, lysine Larginine (:i'Jf.) 1 . 1‘I‘——c{:-—~m-n~~<;jm C 1] Nil; t‘ZiJ'JIi“) ' (ii) i ‘ lul—t1:i—nth-iJm-Lli-ig-n—{Hi—FNI‘i; E l 12‘ M",.* (IN); EvI—(I‘lmi‘fielgfi-"(Ti-i3m-S"-L'.Hg P; NH; 13. $00“ .. H"(Kim-CH1—1".Fir-“£734:mCI‘iffi‘mNHj i 14. Nit? Version 1 09/26/2006 09:25 FAX 512 471 6135 BIOCHEM DIV —> ELECTR RESERVE .002 III. (10 pts) Complete the following with the BEST answers. There may be more than one correct answer. but there is. a BEST anewer. 15. A protein whose activity may be positively or negatively fi—quatenary regulated by binding more than one ligand has structure, 16. . S stabilizes the structure of collagen. ~B—)—microfilaments l7. Proi‘le‘ins that assist other proteins to fold properly are called 43)- intermediate filaments 18. g: is (are) made up of long fibrous subunits. 'D’)‘ collagen 19. Hydrolysis of ATP by l is required for -E)—myosin transport ofrnRNA. protein or other cargo. 20. The "power stroke" refers to the conformation change upon fi-hydroxylysine hydrolysis of ATP by Pg 21. High amounts of promote the stability of '6')- primary collagen by torming crosiilinks, 22. [5 is (are) composed of globular subunits that orient in a -l-l-)- chaperoncs defined polarity. 23. l) ' is a fibrous protein that has a triple helix. -I-)- Hansen: 24. The amino acid sequence is considered the {33" structure. J-)-—hydroxyproline III. (1 pt each) Multiple choice. 25. Which ofthc Following statements is (are) NOT true about restriction endonueleases‘?‘ A They typically recognize and cleave palindromic sequencesw They can function on both RNA and DNA. )t' ) They are used to reproducibly break up large pieces of DNA into discrete fragments. V D) all of the above E) none of the above 26. What is the convention for writing out the amino acid sequence of a peptide? Amino acid sequences are always written with the free carboaylate-group written on the left. and the Neterrninus on the right side.“ Amino acid sequences are always written with the free N-terminus written on the left, and the free carboxylate group on the right side V” C) none are correct 27. Which ofthe following would be the most ful .. 'educed molecule? A) Ctr-non a) (314300014 o) Cnssn 6}) .n. F.) cream 28. The functional groups present in the amino acid threonine are: * aldehyde carboxylic acid, thiol D) thiol, carbonylic acid. amine carboxylic acid. alcohol‘ amine ' E) amine, iniinc, thiol C) ketone, amine, amide 29. Rank the following in terms ot'strength. fi-orn greatest to lowest: A covalent bonds, hydrogen bonds, ionic interactions D) hydrogen bonds, covalent bonds, ionic interactions covalent bonds: ionic interactions, hydrogen bonds E) none ofthe above ) ionic interactions. covalent bonds. hydrogen bonds 30. Which of the tripeptides below hm the largest number of polar R groups? A) Tyr—Lys-Met B) Gly-ProPArg @Asp—Ser-Gln D) ASp-His-Pro l3) Leo-Gln-Ser 31. Which ofthe following are true ofDNA ; _‘ contains both 2' and 3' hydroxyl groups C) missing a 3‘ hydroxyl group @ missing a 2' hydroxyl group D) missing both a 2' and 3' hydroxyl group 32. Which of the following statements about DNA inciting are true'? A) The midpoint ofstrand separation is called the Tm. V" B) The Tm' Is influenced by the G: C content of the strands)!” Separated DNA strands can be renatured by lower ing the temperature slowly. \r/ 11 ot the above E) none of the above 33. In the process of"treadmilling", the net rate ofaddition of actin subunits to one end of the microfilamcnt is in comparison to _I et rate of removal ot'suhunits to the other end. mourn E) greater C) lesser D) none of the above Version 1 Page 2 09/26/2006 09:25 FAX 512 471 6135 BIOCHEM DIV —> ELECTR RESERVE I003 34. Which of the following is the correct equation for thc HendBt'lel-l'lfisselbalcl‘i equation A) plea: pl—'|+log [A']/[HA] D) pH= pKa + [HM/[M E pl-I= -log [H”] E) ~pKa= pH-log [Ad/[HA] PH =PKtl + 193 [A'liU‘iAi iv. (2 pt each) Multiple choice 35. What is the pl-l o‘l’a 2 x [0‘1" solution of HCI'? A) 9.7 B) ID @539 o) 7.1 E) none ofthe above 36. How many hydrogen bonds can i water molecule potentially take part in forming? A) one 13) two C) three .four E) none ofthe above 37. Which ofthe fDIIDWing is NOT true regarding oxyhemoglobin and deoxyhemoglobin? A) deoxyhemogloin has no bound oxygen, whereas oxyhemoglobin may have 1.2.3 or 4- molecules of oxygen boundw l3) 2,3 bisphosphoglycei‘ate binds to deoxyhemoglobin, but not to oxyhetrioglobinw C) the iron in deosyhemoglobin is coordinated to 5 groupsfi‘fitd the iron in on hemoglobin in coordinated to t" D deoxyhemoglobin is in the "tense" state and oxyhemog‘lobin is in the "rel ed" state ._ . _ - 'i-Ci. 0.. @deoxyhemoglobin has a hyperboyf oxygen binding curve, and oxyhcmoglobin has a sigmoidal oxygen binding curve l’L‘JC‘I‘i-l“~ “gnu“ 33. RNA interference (RNAi) is a natural regulatory mechanism that probably evolved to protect cells 17mm invading viruses. Which of the following statements are true? A) RNAi is widely used as a method to study gene regulation V” B) An enzyme called Dicer binds to double stranded RNA and cleaves it into small pieces of RNA that are the "guide" RNAS to target a specific mRNA for degradation V C) microRNA (IniRNA) USES Similar mechanism as RNAi. but miRNA is encoded in the genome and involved in regulation ofgene expression primarily during development, CED“ ofthe above -) none of the above 39. T he disease lathyrism results in animals i'i'Om the ingestion ofsecds from the sweet pea, Lathyrtts odorotns. The seeds contain high levels ofa compound that inhibits lysyl oxidase. What would be the biochemical consequence and what type of symptoms would you expect from this? Based on 5-19. A) inhibititm o-Iz‘actin and myosin resulting in paralysis K ' inhibition ofcrosslinking ofdulteritin resulting in loss ofhair and nails )‘1 @inhibition o't‘erosslinking ozt‘coliagen resulting in defects of the bones and blood vesselsv’ all of the above E) none ofthc above ‘ s aircsloncdvcds 40. At pH | 1.5, the amino groups found in proteins would: fa. 0““ flmL'i—ho SHJUD J (jg-r A) carry a negative charge Ev) carry a positive chage @avc no charge D) bear multiple ionic charges E) none ot’the above 4-1. - - t is the predominant secondary structttrc in amyloid or prion fibers? mi sheet El) ahelix C2) random coil D) random turns E) none oi’the above 4-2. The digestive tract of the larvae of several species of clothes moths is a strongly reducing environment. Why is this beneficial to the iarvae'i' Based on 5-l9. ' A) the primary food scarce. tit-keratin, contains many lysine crosslinlcs and the reducing environment destroys the crosslinks facilitating digestion the primary food source. ct-Iteratin. contains many cysteine crosslinks and the reducing environment destroys the crosslinks facilitating digestion C) all ofthe above D) none cfthe above 43. Which of the following are typical hydrogen bond interactions? N_n, lrl—H, 5—H, H_c)< o) N—H, s_-1~I, I-i—Sil" N—H, 0—H, S—H E) none ofthe above C) o—n, s—n, e—ox 44, in SDS gel electrophoresis which is NQT true: proteins are separated based on their size if" D) the smallest proteins move the fastest through the gel V! only proteins With acidic sicle groups may be separatedi E) all o’r‘thc above the SDS costs the protein with negative chargesx/ Version I Page 3 09/26/2006 09:26 FAX 512 471 6135 BIOCHEM DIV —> ELECTR RESERVE .004 4-5. How does the hydrophobic effect influence the structures nflarg: molecules? A) nonpolar groups are not easily solubilizcd in water and aggregate-r” E) polar groups are oriented on the surface, interacting with the watert‘” C nonpolar groups can mask the polar characteristics of the hydrophilie molecules‘if' A and B E) A tmd C 46. Mutations in enzymes th recess and modify eollagens would NQT be expected to have the following clinical presentation: A) poor danlhealth xcessisfi hair growth C) weak bones D) skin fragility E) no”: ofthc above F) all ofthe above W 4-7. Of the six proteins, actin, myosin, tubulin, kinesin, keratin, and collagen, which are considered to be motor proteins? Based on 5-2. A keratin and collagen D) actin, myosin, tubulin, and kins-sin @myosin and kinesin E) none of the above are correct ) actin and tubulin 48. The Bohr effect on hemoglobin is: ' the increase in oxygen afi'inity in the presence ofexcess heme '7: éthe decrease in oxygen aifinity in the presence of dissolved CO: V the decrease in oxygen affinity in the presence of 2,3-bisphophoglyeeratc ‘K D) the inerease in oxygen affinity in the presence of carbon monoxide K E) none o‘tthe above 49. YDu are a physician with a 45-year-old male patient with swollen gums, petechiae (tiny red spots which result from red blood cells leaking from capillaries into the skin) and thick and scaly skin on the face and fingers. The patient reports occasional gun-i bleeding and joint pain. You suspect that the patient has scurvy, a disease caused by the deficiency of vitamin C (ascorbic acid). He tells you that he smokes 10 cigarettes a day, is trying to lose weight by eating only high— protein foods such as eggs, cottage cheese, and meat, and is under a great deal of stress. What is (are) the biochemical basis of this disease state? Based on 5—28. A) stress prevents the absorption o'l’vitarnin C from floods?» B) the diet of the patient is deficient in vitamin C ‘-"' C) vitamin C is necessary for formation ofdisul‘l‘ide bonds in collagen 74 D) vitamin C is necessary for formation ofhydroxyproline/lysine in collagen \.-r‘ Aand D .B and D A and C H) 13de 50. Of the six proteins, actin, myosin, tubulin, kinesin, keratin, and collagen, which contain nucleotide-binding sites? Based on 5—2' . ‘ fr" .‘-" ‘r" 2- J". A) keratin and collagen D) ctin, myosin, tubuhn, and kins-sin B) myosin and kinesin 1) none of the above are correct C) actin and tubulin 51. You are pcrfon'ning site-directed mutagenesis to test predictions about: which residues are essential for a protein's function. Which of each pair of amino acid substit ns listed below would you expect: to disrupt protein thnction the most? (based on 4-23) A) Val replaccdflby Ala “Pro replaced by His C) Gln replaged by Asn D) Lys replaced by Arg E) none of the above . a: v" 52. In the oxygen binding curves below which curve represents the binding curve of myoglobin: Tillie-II Ling: _.,..._.Ha,m. .... sc' no: can .A s) a C) both A and B are the binding curves for myoglobin, but in different tissucs D) neither resemble the oxygen binding curve of myoglohin Version l Page-4- _I—n-n—"“" ' 09/26/2006 09:26 FAX 512 471 6135 BIOCHEM DIV —> ELECTR RESERVE .005 V. (3 pt. each) READ ALL. the questions in this section before answering any. There is useful information that you may need to answer other I ‘ A- questIonsl ,3.qu Pen 4. $3 ETA ._.in '-" 6“? ‘- K— 53. What is th- urrect ratio ol’dissociated and undissociatcd components to make 0.5 L of0.2 M phosohate buffer, pH 7.7 '? will” A) 10/1 63/1 C) 7.5!] D) 7/1 E) 6.5/1 F) 6/1 G) 5.5M H) 511 l) 4.5/1 J) lr'l Dfil‘ e 5g; 54. [Note: this problem may require extra time. do not attempt until the rest oi’tlte exam is complete.) 37 = LIE-IA VI. ._._. _.__JIIU—dl To make a phosphate buffer you discover you only have solid Nat-111304 (MW 120 g/mcl). Which is the most correct "recipe" to make 0.5 L f0.2 M phosphate buffer, pH 7. 7? A) 6 g a 8 mL. 2 M NaO Alissa-ware” l2 g NaHzPOt 83 ML 2 M Mac)”, 412 mL water 3) 6 g NaflzP a. 4 ‘ aOl-l. 456 mL new 12 g NaI-lsPO-tfld mL 2 M NaOH, 456 mL water C) 6.2. .. 4,221TILZMH 141:" water 12 g Nat-lzili'Oa. 22 mL 2 M NaOl-l. 473 ml. water 55. YOU wish to prepare 0.5 L cut-'02 M phosphate buffer at pH 7.7. wr'gfihe relevant equation and plia? \ A) H3130: ~:—--:~ Hanoi-lat tr. pKa= 22 14.113le 2...} HP 41+ Ht, pKa=6.8 E) l-IP‘CIt-2 «:me 004‘3 + H”: pKa =12.4 none of the above 56. [Noon this problem may require extra time, do not attempt until the rest of the exam is complete] I\ . Goo ML- What amount of 0.2 M Noll-12130:; and 0.2 M NazHPOn would be required to make 0.5 L ot‘0.2 M phosphate buffer, pH 7.7? l A) 4-4-4 mL 0.2 M. NaHzPOu and 56 mL 0.2 M Nazi-IP04 D 400 ITIL 0.2 M NaHePO-I and |00 ml. 0.2 M Noel-11304 ll B) 334 mL 0.2 M NEIHIFCM and [66 mL 0.2 M NaaHPDt (@556 :mL 0.2 M Nat-12130.4 and 444 mL 0.2 M NHZHPQ-t C) 143 ml. 0.2 M NazHP04 and 357 mL 0.2 M Natl-121304 ‘357 mL 0.2 M Natl-IP04 and 143 mL 0.2 M Hal-121504 \ 3 1600: Lid-14ml, PI" Vq “53‘3“ 5 (““9" ”A T (sooth j a terrace) 57. (3 pts) Seedlings use seed storage proteins as an important nitrogen source during germination. A new seed storage protein was discovered in Brossica reign: and named EN. The protein was purified and an attempt was made to sequence the protein by Edrnan degradation. However, this was unsuccessful because the amino terminus was apparently blocked. Based on comparisons with other proteins in the some family whose sequences are known, the investigators hypothesized that the amino terminal residue was N~acetyl serine. ‘ If N—aeetyl-serine is indeed the N-terminal residue, the Edman degradation should have been successful because the Edman reagent would react with the N—acetyl group. This statement is true or false. Based on 4—19. A True m also 58. (3 pt) The peptide hormone glucagon from the Nile tilapia was treated with chymotrypsin and the resulting fiagments were sequenced. A second sample of the polypeptide was heated with oypsin and the fragments were sequenced. What Is the sequence of the polypeptide? Based 0114—16.// Chymotrypsin Fragments T rypsin Fragments (3 LEDRKAQDF @Hssotrsunvsn (33l LMNNKasoAAE C9 AQDrvRWLMNNK assert 371.13sz fl/ sum RSGAAE a nut :12? 3 set rt host? it“ it i’ ’ A) HSEGTFSK‘I’SNDYLEDRKAQDFVRWLWNKRSGAAIE i / H? (30.4 ( [4AA "id to a l—lSEGTFSNDYS-KYVRWLEDItKAQDFLh/WNKRSGAAE for - ‘ ISEGTFSNDYS venom: Q rvuw MNNKRSGAAE _.w 30 ,2 , _‘ <g‘)>ont:otr.sa.o (:3) EM‘ ‘DI‘L\KOZNl“Dlm’Qfi‘ “1P ’5 . o a. _._..._..-._. ._.fD—rr", “/10 i Mflifl )6 i20% imt‘tifl q ‘__._,..H__... _ WW .fi_,___-l.....——-v—d" " "“ H (”‘3' ELLA‘C H) ngq ”Lid“ 11.32.14. Cam up" LEI-L L; A’i‘yw LL.H..»L£\_ “Ch-.0 '72-‘60?“ 0.1molev' Wq 3 0.098 mole 0E " 0.086 mole = 0.,ot.lt.\L —. ___,__.._—--"' ‘ zntmebh' Version 1 Page 5 ‘ + 46 (.0 firti {:5 cm r'I-LL 09/26/2006 09:27 FAX 512 471 6135 BIOCHEM DIV —> ELECTR RESERVE I006 v11_ (3 pr each) (based on 4-53) While most human beings are able to hold their breath for only a minute or two, other species are able to stay under water For much longer periods of time. A recent sci-iii television program Invasion, suggested that a human-alien hybrid could live both on land and underwater. One clue was these who had been “changed" by an encounter in the water with the aliens had elevated levels of hemoglobin, but not myogiobi'n and BPG was absent. Various physiological adaptations allow some organisms (or aliens) to deliver oxygen to tissues while submerged. For example, deep sea—diving mammals, such as whales and seals, are able to stay under water for long periods of time because their muscles contain many—fold higher concentrations of myoglobin than humans. The alien-human hybrids are able to stay submerged for long periods of time under water. We are hypothesizing that since the myoglobin levels are not elevated in the alien- hybrids, that there is an efficient mechanism for release of the oxygen from the hemoglobin to be taken up by the myoglobin. Croccodiles are known to use bicarbonate for this purpose. 3 Read all questions before answering. l 59. The researchers decided to modify human hemoglobin to mimic alien-humanhemoglobin. They identified 3 amino acid residues that most likely contacted the bicarbonate directly. These amino acid differences are most liltely where? A) surrounding the heme binding pocket )4 D) none ofthc above in the Cit—helix with the distal histidine "it E) all ‘o‘l’the above t the tit/B dimer interface V ‘ 60. Consider the hypothesis that bicarbonate serves as an allosteric modulator of oxygen binding in alien-human hybrids. What would be the source ofbicarbonate in tissues while submerged in ocean water? A) CD: is produced by metabolic processes and forms carbonic acid V B) Carbonic acid rapidly dissociates to form protons and bicarbonate in the presence ofcarbonic unhydrase / C02 is released during the dark cycle of photosynthesis by water plattts/aigaefplankton and absOrbed X A and B i E) " B and C ! F) all of the above i 61. Which curve would represent the binding of oxygen to alien-human hemoglobin in the presence of bicarbonate? _.--I B release DE. 51i- LiML-ESLL-r l3 Ctr Limit pr: Elected-e p09. A) A as C) neither are correct ‘ I52. investigations of allosl:eric regulators of Hi: in other species discovered that dirds use myo-inositol pentaphosphate and fish species use either ATP or GTP. What is the mechanism tbr these compounds to promote allosteric regulation of Hb'? 7" A) these are all hydrophobic compounds that: would interact with the hydrophobic core and cause changes in the protein structure FAB) these are all positively charged compounds that would bind to amino acids such as glu or asp or the carboxy termini ofthc Hh . subunits and cause changes in the protein structure @Lhese are all negatively charged compounds that would bind to amino acids such as erg, lys or the amino termini of the Hb subunits and cause changes 1n the protein structure - D) none of the above Version 1 Page 6 09/26/2006 09:27 FAX 512 471 6135 BIOCHEM DIV —> ELECTR RESERVE .007 Answer Key PFHQMPP‘JE‘J!‘ w an OWUOOWWDHW>wuwwmwuwmw>onumunm>Uwnwmuwmmumwmromu?—>mn—}fi?anf0mm x Version I Page”! ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern