Copyright Cengage Learning Powered by Cognero Page 1 Indicate the answer choice that best completes the statement or answers the question Section I 24 points 2 points each 1 How do the molecules that play a role in living cells compare to those encountered in organic chemistry a They are the same just operating in a different context b Biological molecules are organic molecules but the similarity ends there c Biological molecules aren t similar to organic molecules at all d Biology isn t based on molecules at all but a vital force 2 If heat thermal energy is absorbed by the system during a chemical reaction the reaction is said to be a exergonicb endergonicc exothermicd endothermice at equilibrium3 Indicate whether the following structures are present in prokaryotic cells a nucleusb cell membranec endoplasmic reticulumd mitochondriae b and d 4 Which of the following molecules contains a thiol group A B C D E a Ab Bc Cd De E5 Non polar molecules experience a small attractive force owing toa ionic interactionsb hydrogen bondsc London dispersion forces induced dipole d all of the abovee none of the aboveName Class Date Practice Exam 1 Copyright Cengage Learning Powered by Cognero Page 2 6 If atoms with greatly differing electronegativities form a bond that bond will bea polar b nonpolar c amphipathic d acidic 7 At its isolectric pH glycine will havea both of its ionizable functional groups charged b neither of its ionizable functional groups charged c only its carboxyl group charged d only its amino group charged 8 Which amino acid has a basic R group a Glutamic Acidb Histidinec Isoleucined Serinee Tyrosine9 A single amino substitution can give rise to a malfunctioning protein a Trueb False10 Heme would best be described as aa motif b domain c prosthetic group d helix 11 In SDS gel electrophoresisa proteins are separated based on their molecular weightb only proteins with aromatic amino acids may be separatedc the largest proteins move the farthestd all of the above12 Which technique involves the determination of protein primary structure by a chemical sequencing method a Edman sequencingb Mass spectrometryc Size exclusion chromatographyd X ray crystallographye SDS PAGE electrophoresisName Class Date Practice Exam 1 Copyright Cengage Learning Powered by Cognero Page 3 Section II 76 points 4 points each 13 The enthalpy change H for the formation of ammonia from hydrogen and nitrogen is 46 11 kJ mol This reactionis a exergonicb endergonicc exothermicd endothermice at equilibrium14 Prokaryotesa contain ribosomesb do not have a cell membranec contain mitochondriad none of the above15 You are given data that shows the G of the reaction below to be approximately 31 5 kJ mol In the laboratory youmeasure an enthalpy value of 4 3 kJ mol and an entropy value of 73 4 J mol At what temperature must thisreaction take place in order to reach the experimentally determined G value Phosphoenolpyruvate ADP Pi Pyruvate ATPa 80 Cb 371 Cc 298Kd 371Ke 97K16 How many H bond donor atoms are present in the molecule below a 2b 3c 4d 5e 6Name Class Date Practice Exam 1 Copyright Cengage Learning Powered by Cognero Page 4 Exhibit AThe structure of ATP with various groups labeled is pictured below Group III is the entire phosphate group 17 Refer to Exhibit B Which of the functional groups is the most electrophilic a Ib IIc IIId IVe The answer cannot be determined without further information 18 What is the pH of 1 0 L of water to which 25 mL of 1 0 M HCl has been added a 6 4b 1 6c 7 0d 4 4e 8 419 The acid HA has a dissociation constant Ka of 1 5 x 10 4 The ratio A HA for a solution of this acid base pair atpH 8 5 is approximatelya 1500b 50 000c 0 95d 0 03e none are correct20 At which pH would you expect the amino acid histidine to be most soluble a pH 1b pH 4c pH 8d pH 13Name Class Date Practice Exam 1 Copyright Cengage Learning Powered by Cognero Page 5 21 Several common amino acids are modified to produce biologically important amines Serotonin is a neurotransmittersynthesized in the brain that has been linked to depression aggression and hyperactivity at levels that are lower thannormal Given the structure below from what amino acid is serotonin derived a Yb Wc Td Fe P22 Which of the tripeptides below has the largest number of polar R groups a Tyr Lys Metb Gly Pro Argc Asp Ser Glnd Asp His Proe Leu Gln Ser23 What is the net charge on the following peptide at pH 5 I T S H A R D W Y R Ka 1b 0c 1d 2e 324 What type of covalent bond is responsible for holding together the secondary structure of proteins a Disulfide bondsb Hydrogen bondsc Amide bondsd Ionic bondse None of the above25 Which of the following statements regarding the oxygen affinities of myoglobin and hemoglobin is TRUE a The affinity of Mb remains high at all O2 concentrations b The affinities of each of the 4 subunits of Hb are independent of each other c Hb exhibits different affinities at low versus high O2 concentrations d Hb binds the first molecule of O2 more readily than the last Name Class Date Practice Exam 1 Copyright Cengage Learning Powered by Cognero Page 6 26 Which of the following is true a The peptide bonds in the sheet are extended b The peptide bonds in the helix coil back on themselves c Both helices and sheets can be found as part of tertiary structure d All of these27 Hundreds of hemoglobin variants are known but one of the better known variants is sickle cell hemoglobin Hb S The protozoan that causes malaria Plasmodium falciparum slightly decreases the pH of the red blood cells itinfects Are Plasmodium infected cells more or less likely to undergo sickling in individuals with the Hb S variant a More likelyb Less likelyc Equally likely28 Which peptide would elute first from a DEAE diethylaminoethyl cellulose column anion exchange with decreasingpH gradient a ADGEMb ADGKMc ADEKRd AMGKRe AMGER29 An amino acid mixture consisting of pheylalanine glycine and glutamic acid is to be separated by reverse phaseHPLC The stationary phase is nonpolar and the mobile phase is a polar solvent at neutral pH Which one will movethe fastest a Pheb Glyc Glu30 Given the information below which protein will migrate to the anode positive electrode at pH 5 9 Protein pIMyoglobin 6 8Cytochrome c 9 3Carbonic anhydrase 4 9a myoglobinb cytochrome cc carbonic anhydrase31 Which of the following proteins would elute first in size exclusion chromatography Note kDa kiloDalton 1 Da 1 g mol a Hemoglobin 64 5 kDa b Myoglobin 16 7 kDa c Actin 42 0 kDa Name Class