Biochemistry 305 Fall 2013 Exam 1 1 The following chemical transformation is an example of what type of reaction a Addition b Elimination c d Nucleophilic substitution e Oxidation reduction Isomerization 2 Which force is not a weak force a Hydrogen bonds b Van der Waals interactions c Covalent bonds d e Hydrophobic interactions Ionic interactions H2O COO CH CH COO COO HC OH CH COO 3 Which of the statements about the nature of the hydrogen bond is FALSE a The donor is a hydrogen atom bonded to an atom that is more electronegative than hydrogen b The more linear the bond the stronger the interaction c The acceptor must be more electronegative than hydrogen d e A hydrogen bond is a type of hydrophobic interaction 4 Which statement about hydrophobic interactions is TRUE It is a type of non covalent bond a They lead to the clustering of non polar molecules when added to b They result because water molecules prefer to hydrogen bond with c They result from ionic interactions between water and non polar an aqueous solution non polar molecules molecules d They are a major force that stabilizes primary structure in proteins e They result in polar and charged regions of biological molecules being buried in the molecule s interior excluding those regions from the aqueous environment 5 Which of these statements about the properties of water is FALSE a Ability to form hydrogen bonds b High dielectric constant enables solvation of ions c Ability to orient around non polar solutes to promote hydrophobic interactions d Can dissociate to form H and OH ions e None all are true 6 Ice is less dense than liquid water because a The hydrogen bonds are longer in ice b Water has a lower dipole moment at low temperatures c The hydrogen bonds are unable to form in ice d The half life of hydrogen bonds is shorter in ice e Water is unable to dissociate into H and OH at low temperatures 7 The pH of pure water is 8 Grapefruit juice pH 3 2 contains times as much H as orange juice 9 The pH of a 0 166 M monoprotic acid solution is 6 09 What is the pKa of 10 Which of the following is NOT an intrinsic property of ALL 20 standard amino acids a Chiral b The capacity of polymerize c Acid base chemistry d Varied structure and chemical functionality in side chains e Act as polyprotic acids 11 Which of the following amino acids is classified as a basic amino acid 12 Which amino acid is shown here H N H H C CH O C OH H3C CH3 13 Which amino acid lacks BOTH a free alpha amino and a free alpha a 0 b 7 c 7 4 d 14 e 55 5 pH 4 3 a 0 74 b 7 9 x 10 2 c 110 d 12 6 e 1 34 the monoprotic acid a 0 78 b 5 92 c 6 26 d 8 13 e 11 4 a Leucine b Phenylalanine c Aspartatic acid d Asparagine e Lysine a Asp b Val c Ala d Ser e Leu carboxyl group a Aspartic acid b Lysine 14 At what pH value would Histidine have a net negative charge 15 Calculate the isoelectric point for glutamic acid 16 What feature of the peptide bond limits rotational movement around the C a Hydrogen bonding between the carbonyl and the alpha carbon b Electrostatic attraction between COO and NH3 c Electrostatic repulsion from adjacent COO groups d Steric hindrance from side groups e Partial double bond character groups 17 What is the overall net charge of the peptide K K N E 18 An ionic interaction could occur within a protein between the R groups of which pair of amino acids at physiological pH 19 A common reaction of 2 Cys residues in proteins results in the formation c Asparagine d Proline e Valine a 1 0 b 4 0 c 6 0 d 8 0 e 11 0 a 2 20 b 3 25 c 4 30 d 5 95 e 7 00 N bond a 2 b 1 c 0 d 1 e 2 a Asp Glu b Val Leu c Tyr Cys d Arg Lys e Lys Glu of a Thioester bonds b Disulfide bonds c Dithiol bonds 20 Alpha helices and Beta sheets are components of what level of protein 21 Formation of a trimer would be an example of what level of protein d Thioether bonds e Hydrogen bonds structure a Primary b Secondary c Tertiary d Quaternary structure a Primary b Secondary c Tertiary d Quaternary 22 Alpha helices are stabilized primarily by a Hydrogen bonds between the main chain peptide bond component atoms chain b Electrostatic interactions between R groups c Hydrophobic interactions between the alpha carbons of the main d Hydrogen bonds between the R groups e Hydrophobic interactions between R groups and the solvent water 23 Which protein s will bind strongly to an anionic exchange column at pH 7 5 Protein A Protein B Protein C Protein D 236 kD 22 kD 68 kD 43 kD pI of 8 4 pI of 6 3 pI of 9 7 pI of 7 5 a B b C c D d A and C e B and D 24 Which mutation would be LEAST likely to impact the folding and or function of the protein a Lys to Ser 25 To fold properly a peptide absolutely requires which of the following 26 Pellagra is the result of a deficiency in what amino acid b Ala to Asp c His to Pro d Val to Ile e Phe to Tyr a Chaperones b Non reducing conditions c Aqueous environment d Both a and c e Both b and c a Tyrosine b Lysine c Phenylalanine d Threonine e Tryptophan 27 Which statement is FALSE about prokaryotic cells a Some have a flagella b All have a plasma membrane c All have nucleus d All have ribosomes e All lack mitochondria 28 A mixture of proteins is loaded onto a gel filtration column with a sizing range of 40 150 kD In what order will the proteins be eluted from the column first to last Protein A Protein B Protein C Protein D 236 kD 22 kD 68 kD 43 kD pI of 8 4 pI of 6 3 pI of 9 7 pI of 7 5 a C A D B b B D A C c A C D B d B D C A e B D A C
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