Ch.24 Amino Acids And Proteins Verified Test Bank - Organic Chemistry 13e | Test Bank by Solomons by Graham Solomons. DOCX document preview.
Package Title: Solomons Test Bank
Course Title: Solomons 12e
Chapter Number: 24
Question type: Multiple choice
1) Which amino acid is unlikely to be found in a natural protein?
a) IV
b) III
c) II
d) V
e) I
Topic: Amino Acid Structure
Section: 24.1
Difficulty Level: Easy
2) Which of these amino acids has the R configuration at the stereogenic center but, nonetheless, is an L amino acid?
a) I
b) II
c) III
d) IV
e) V
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
3) Which of these amino acids cannot be described as an l-amino acid?
a) I
b) II, IV and V
c) I and III
d) II and IV
e) III and V
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
4) Which of these amino acids is a D amino acid?
a) I
b) II
c) III
d) IV
e) V
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
5) Which of these amino acids is(are) R amino acid(s)?
a) II and IV
b) IV and V
c) I and III
d) V
e) All of these are R amino acids.
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
6) Which of the following amino acids is theoretically capable of existing in diastereomeric forms?
a) I
b) II
c) III
d) IV
e) V
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
7) Which amino acid is achiral?
a) I
b) II
c) III
d) IV
e) V
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
8) Which of these amino acids contains a hydrophobic side chain?
a) Lysine
b) Serine
c) Methionine
d) Arginine
e) Cysteine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
9) Which of these natural amino acids contains an amide function?
a) Asparagine
b) Proline
c) Arginine
d) Histidine
e) None of these choices.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
10) Which of these natural amino acids contains a heterocyclic ring?
a) Asparagine
b) Proline
c) Arginine
d) Histidine
e) Proline and histidine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
11) Which of these natural amino acids contains an amide function?
a) Asparagine
b) Glutamine
c) Methionine
d) Cysteine
e) Two of these
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
12) Which of these natural amino acids contains two carboxylic acid groups?
a) Aspartic acid
b) Cysteine
c) Glutamic acid
d) Cystine and cysteine
e) Aspartic acidand glutamic acid
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
13) Which of these natural amino acids contains a phenolic group?
a) Phenylalanine
b) Tyrosine
c) Tryptophan
d) 4-Hydroxyproline
e) Serine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
14) Which of these natural amino acids contains a pyrrolidine ring?
a) Phenylalanine
b) Tyrosine
c) Tryptophan
d) 4-Hydroxyproline
e) Serine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
15) Which of these natural amino acids contains an indole ring?
a) Phenylalanine
b) Tyrosine
c) Tryptophan
d) 4-Hydroxyproline
e) Asparigine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
16) Which of these natural amino acids contains an imidazole ring?
a) Histidine
b) Lysine
c) Tryptophan
d) 4-Hydroxyproline
e) Two of these choices.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
17) Which of these natural amino acids contains an –OH group?
a) Serine
b) Threonine
c) Tyrosine
d) Two of these.
e) All of these choices.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
18) Disulfide bonds in proteins:
a) result from an oxidation of thiols.
b) help to maintain the shape of proteins.
c) can be broken by reduction.
d) can link two cysteine amino acid residues.
e) All of these choices.
Topic: Protein Structure
Section: 24.2
Difficulty Level: Easy
19) Which of these natural amino acids, when present in a polypeptide, is likely to exhibit significant hydrogen bonding through its side chain?
a) Serine
b) Threonine
c) Tyrosine
d) Two of these choices.
e) All of these choices.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
20) Which of these natural amino acids, when present in a polypeptide, is not likely to exhibit significant hydrogen bonding through its side chain?
a) Leucine
b) Threonine
c) Tyrosine
d) Serine
e) All of these are likely to exhibit significant hydrogen bonding through the side chain.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
21) Which of these amino acids is formed from a precursor amino acid only after the latter has been incorporated into a polypeptide chain?
a) Serine
b) Arginine
c) Isoleucine
d) Tryptophan
e) Hydroxyproline
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
22) Pipecolic acid logically would be substituted for which natural amino acid in the synthesis of peptide analogs?
a) Histidine
b) Proline
c) Tryptophan
d) Phenylalanine
e) Tyrosine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Medium
23) Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?
a) Tyrosine
b) Proline
c) Tryptophan
d) Phenylalanine
e) Histidine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Medium
24) Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?
a) Methionine
b) Cysteine
c) Cystine
d) Tyrosine
e) It could be substituted for all of these amino acids.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Medium
25) Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?
a) Aspartic acid
b) Glutamine
c) Lysine
d) Asparagine
e) Glutamic acid
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Medium
26) What is the name of the aminoacids F; E; R, respectively:
a) Proline, aspartic acid, asparagine.
b) Proline, methionine, cysteine.
c) Phenylalanine, glutamic acid, arginine.
d) Proline, glutamic acid, glutamine.
e) Phenylalanine, asparagine, glutamine.
Topic: Naming
Section: 24.2
Difficulty Level: Medium
27) Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?
a) Leucine
b) Lysine
c) Arginine
d) Alanine
e) Valine
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Medium
28) Which of these amino acids is described as an “essential” amino acid?
a) Threonine
b) Glycine
c) Tyrosine
d) Serine
e) All of these are “essential” amino acids.
Topic: General
Section: 24.2
Difficulty Level: Easy
29) Which of the following sets of amino acids are essential amino acids:
a) Lysine, glutamic acid, asparagine.
b) Phenylalanine, threonine, lysine.
c) Threonine, tyrosine, tryptophan.
d) Proline, cysteine, hydroxyproline.
e) Arginine, histidine, lysine.
Topic: General
Section: 24.2
Difficulty Level: Easy
30) Which of these amino acids is described as an “essential” amino acid?
a) Methionine
b) Phenylalanine
c) Isoleucine
d) Tryptophan
e) All of these are “essential” amino acids.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
31) Which amino acid would have its isoelectric point near pH 10?
a) I
b) II
c) III
d) IV
e) V
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
32) Which amino acid would have its isoelectric point near pH 3?
a) I
b) II
c) III
d) IV
e) V
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
33) Which amino acid would have its isoelectric point near pH 10?
a) Glycine
b) Tryptophan
c) Serine
d) Proline
e) Lysine
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
34) Which amino acid would not have its isoelectric point in the pH range 5-7?
a) Leucine
b) Threonine
c) Methionine
d) Arginine
e) Cysteine
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
35) Which amino acid would not have its isoelectric point in the pH range 5-7?
a) Glycine
b) Proline
c) Cysteine
d) Glutamine
e) All of these amino acids have isoelectric point in the pH range 5-7
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
36) What might be concluded upon determining that an unknown amino acid has its isoelectric point near pH 10?
a) It must have a hydrophobic side chain.
b) It must have a hydrophilic side chain.
c) Its side chain must contain more basic groups then acidic groups.
d) Its side chain must contain an acidic group.
e) None of these choices is a valid conclusion.
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
37) What might be concluded upon determining that an unknown amino acid has its isoelectric point near pH 3?
a) It must have a hydrophobic side chain.
b) It must have a hydrophilic side chain.
c) Its side chain must contain a basic group.
d) Its side chain must contain more acidic groups then basic groups.
e) None of these choices is a valid conclusion.
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
38) The pH at which the concentration of the dipolar ion (zwitterion) form of an amino acid is at a maximum and the cationic and anionic forms are at equal concentrations is termed the
a) end point.
b) equivalence point.
c) neutral point.
d) isoelectric point.
e) dipolar point.
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
39) What is the pI of the following amino acid?
a) 1.2
b) 3.2
c) 5.5
d) 6.2
e) 7.0
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
40) What is the pI of the following amino acid?
a) 2.1
b) 5.9
c) 3.2
d) 6.5
e) 7.0
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
41) What is the pI of the following amino acid?
a) 1.5
b) 6.3
c) 5.6
d) 9.8
e) 7.2
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
42) What is the pI of the following amino acid?
a) 12.0
b) 3.6
c) 4.8
d) 6.0
e) 7.2
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
43) What would be the predominant form of lysine in water at pH 14?
a) I
b) II
c) III
d) IV
e) V
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
44) The predominant form of aspartic acid in water at pH 1 would be:
a) I
b) II
c) III
d) IV
e) V
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
45) For the accompanying fully-protonated amino acid, what is the arrangement of pKa values in order of increasing magnitude?
a) I < II < III
b) II < I < III
c) III < I < II
d) III < II < I
e) II < III < I
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Medium
46) What is the pI of phenylalanine (pKa1 = 1.8; pKa2= 9.1)?
a) 2.3
b) 1.8
c) 5.5
d) 9.1
e) 10.9
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Medium
47) What is the pKa of the carboxylic acids present in the following compounds in the given order:
a) 10.1; 2.32; 4.45
b) 2.32; 2.32; 5.00
c) 4.45; 3.22; 4.75
d) 2.32; 4.50; 4.75
e) 3.47; 2.32; 4.45
Topic: General
Section: 24.2
Difficulty Level: Hard
48) Which is an isolable intermediate in the Strecker synthesis of an amino acid?
a) I
b) II
c) III
d) IV
e) V
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Easy
49) Which of the following would provide a synthesis of alanine?
a) CH2=CHCH2OH, HBr; then CrO3/H2SO4/H2O; then excess NH3
b) Potassium phthalimide, ClCH2CO2C2H5; then KOH/H2O; then HCl
c) Potassium phthalimide, C6H5CH2Br; then KOH/H2O; then CO2, H3O+
d) CH3CH2COOH, (C6H5)3CNa; then NH3
e) Two of these choices.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
50) Which of the following would provide a synthesis of valine?
a) Potassium phthalimide, (CH3)2CHCHClCO2C2H5; then KOH/H2O; then HCl
b) (CH3)2C=CHCH2OH, HBr/peroxides; then CrO3/H2SO4/H2O; then excess NH3
c) Potassium phthalimide, (CH3)2CHCH2Br; then KOH/H2O; then CO2, H3O+
d) CH3CH2COOH, (C6H5)3CNa; then NH3
e) Two of these choices.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
51) Which of the following would provide a synthesis of leucine?
a) (CH3)2C=CHCH2OH, HBr/peroxides; then CrO3/H2SO4/H2O; then excess NH3
b) Potassium phthalimide, BrCH(CO2C2H5)2; then (CH3)2CHCHClCO2C2H5, NaOEt; then KOH/H2O; then HCl, heat
c) Potassium phthalimide, BrCH(CO2C2H5)2; then (CH3)2CHCH2Br, NaOEt; then KOH/H2O; then HCl, heat
d) (CH3)2CHCOOH, PCl5; then NH3
e) Two of these choices.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
52) Which of the following would provide a synthesis of phenylalanine?
a) Phenylacetaldehyde, NH3, HCN; then H3O+ and heat
b) Potassium phthalimide, BrCH(CO2C2H5)2; C6H5CH2Br, NaOEt; then NaOH; then HCl, heat
c) Potassium phthalimide, (C6H5)CH2CH2Br; then KOH/H2O; then HCl, heat
d) C6H5CH2COOH, SOCl2; then NH3
e) Two of these choices.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
53) What product(s) would you expect from the following reaction?
a) I
b) II
c) III
d) IV
e) V
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
54) Why is this sequence, CH2=CHCH2OH + HBr, then CrO3/H2SO4/H2O, finally excess NH3, not a good method for the preparation of l-alanine?
a) NH3 is not sufficiently nucleophilic to perform the final step.
b) HBr does not add to substituted alkenes.
c) 1° alcohols are not oxidized by CrO3 in acidic solution.
d) Initial HBr addition produces a racemic intermediate which leads to racemic product.
e) Steric hindrance precludes nucleophilic substitution at a 2° carbon atom.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
55) What is the product of the treatment of a racemic form of dl-phenylalanine with acetic anhydride followed by treatment with deacylase enzyme?
a) S-Phenylalanine
b) R-Phenylalanine
c) d-Phenylalanine
d) Both are hydrolyzed
e) The mixture is not affected by this enzyme.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
56) Which one of these amino acids does not give the usual purple color with ninhydrin?
a) Histidine
b) Proline
c) Tryptophan
d) Leucine
e) Aspartic acid
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.4
Difficulty Level: Easy
57) The purple color of the anion formed in the ninhydrin test for α-amino acids is due to:
a) the attraction of the anion to a metal in a pi-complex.
b) intermolecular hydrogen bonding.
c) molecular vibrations.
d) the highly conjugated nature of the anion.
e) the color of the ninhydrin.
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.4
Difficulty Level: Medium
58) What methods can be used for the identification of amino acids?
a) Amino acid analyzer using cation-exchange resin
b) Cation-exchange resin packed column in an HPLC instrument
c) Column chromatography on normal phase silica gel
d) Reaction with ninhydrin followed by IR spectroscopy
e) Two of these choices.
Topic: Analysis
Section: 24.5
Difficulty Level: Easy
59) A pentapeptide has the molecular formula: Asp, Glu, His, Phe, Val. Partial hydrolysis of the pentapeptide gives: Val·Asp, Glu·His, Phe·Val, and Asp·Glu. What is the amino acid sequence of the pentapeptide?
a) Phe·Val·Asp·Glu·His
b) His·Glu·Asp·Val·Phe
c) Asp·Glu·His·Phe·Val
d) Phe·Val·Glu·His·Asp
e) Glu·His·Phe·Val·Asp
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.5
Difficulty Level: Easy
60) A heptapeptide Ala2, Glu, Phe, Pro, Tyr, Val gives labeled alanine when heated with DNFB followed by hydrolysis. On partial hydrolysis the unlabeled heptapeptide gives the following:
Ala·Glu, Pro·Tyr, Ala·Val, Tyr·Ala, Val·Phe·Pro.
What is the amino acid sequence of the heptapeptide?
a) Ala·Phe·Pro·Tyr·Ala·Glu·Val
b) Ala·Val·Phe·Pro·Tyr·Ala·Glu
c) Ala·Val·Phe·Pro·Tyr·Glu·Ala
d) Ala·Val·Phe·Tyr·Pro·Ala·Glu
e) Val·Ala·Phe·Tyr·Pro·Ala·Glu
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.5
Difficulty Level: Easy
61) When the pentapeptide below is heated first with 2,4-dinitrofluorobenzene (and base) and then subjected to acidic hydrolysis, which amino acid will bear the dinitrophenyl group?
Leu·Val·Gly·Phe·Ile
a) Leucine
b) Valine
c) Glycine
d) Phenylalanine
e) Isoleucine
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.5
Difficulty Level: Easy
62) The Edman degradation uses this reagent to identify the N-terminal amino acid of a peptide or protein.
a) C6H5NHNH2
b) C6H5NH2
c) C6H5N=C=S
d) C6H5N=C=O
e) Aminopeptidase
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.5
Difficulty Level: Easy
63) The primary structure of a protein refers to its:
a) sequence of amino acid residues.
b) disulfide bonds.
c) helical structure.
d) hydrogen bonding.
e) All of these choices.
Topic: Protein Structure
Section: 24.5
Difficulty Level: Easy
64) How many different tripeptides can exist, each containing one residue of glycine, one of l-threonine, and one of l-arginine?
a) 2
b) 3
c) 6
d) 8
e) 9
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.5
Difficulty Level: Easy
65) Which amino acid of a polypeptide would become labeled when the polypeptide is treated with 2,4-dinitrofluorobenzene in base, even though the amino acid is not a terminal amino acid?
a) Lysine
b) Glycine
c) Alanine
d) Phenylalanine
e) Leucine
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.5
Difficulty Level: Medium
66) Which of these are methods to determine the sequence of amino acids in a peptide?
a) Ladder sequencing; partial hydrolysis and sequence comparison.
b) Partial hydrolysis; tandem mass spectrometry and IR.
c) Partial hydrogenolysis and mass spectrometry.
d) Edman’s degradation and NMR.
e) DNFB in acid, Edman’s degradation and labeling.
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.6
Difficulty Level: Medium
67) This reagent is used to "protect" the amino group of an amino acid which is to be joined to a second amino acid by a peptide bond.
a) 
b) 
c) 
d) 
e) 
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.7
Difficulty Level: Easy
68) Why is dicyclohexylcarbodiimide (DCC) used in peptide synthesis?
a) DCC "protects" the amino group of the intended N-terminal amino acid.
b) DCC activates the carboxyl group of one amino acid so that this amino acid reacts more readily with a second amino acid.
c) DCC cleaves the blocking groups from the final peptide.
d) DCC is the resin used in the automated synthesis of peptides.
e) DCC removes the peptide from the resin at the conclusion of the synthesis.
Topic: Peptide Sequencing, Labeling, and Synthesis
Section: 24.7
Difficulty Level: Easy
69) What product would be obtained upon treating alanine with the following reagent?
a) I
b) II
c) III
d) IV
e) V
Topic: Synthesis and Reactions of Amino Acids
Section: 24.7
Difficulty Level: Medium
70) Which one is the correct reaction sequence for the attachment of valine on the N-terminus of a growing peptide?
a) Amino group deprotection, addition of Val and base, heating.
b) Amino group cleavage on Val, activation of carboxylic acid functionality on growing peptide chain, reaction between the two.
c) Amino group protection on the growing peptide chain, activation of the carboxylic acid functionality on Val, reaction with growing peptide.
d) Amino group deprotection on growing peptide, activation of the carboxylic acid functionality on Val, reaction with growing peptide.
e) Mix Val and growing peptide, add base and incubate the two for a period of time.
Topic: Synthesis
Section: 24.7
Difficulty Level: Medium
71) The secondary structure of proteins is derived from:
a) peptide linkages.
b) disulfide linkages.
c) hydrogen bond formation.
d) hydrophobic interactions.
e) acid-base interactions.
Topic: Protein Structure
Section: 24.8
Difficulty Level: Easy
72) Which attractive force is responsible for maintaining the tertiary structure of a protein?
a) Disulfide linkages
b) Hydrogen bonds
c) van der Waals forces
d) Hydrophobic interactions
e) All of these choices.
Topic: Protein Structure
Section: 24.8
Difficulty Level: Easy
73) The occurrence of this amino acid in a polypeptide chain disrupts an α-helix:
a) Proline
b) Alanine
c) Methionine
d) Histidine
e) Tyrosine
Topic: Protein Structure
Section: 24.8
Difficulty Level: Easy
74) What statements are true about enzymes?
I) They are biological catalysts, non-specific, that increase the reaction rate by 1000 times.
II) They are catalysts that increase reaction rates by a factor or 1 million or more.
III) Enzymes are remarkably specific, leading Fischer to formulate a lock-and-key hypothesis.
IV) Enzymes undergo an induced fit upon binding the substrate.
V) Enzyme and substrate form a complex
a) I, III, V
b) II, III, V
c) I, III, IV, V
d) II, III, IV, V
e) III, V
Topic: Introduction to Enzymes
Section: 24.9
Difficulty Level: Easy
75) What is the induced fit in an enzyme?
a) It is the formation of hydrogen bonding between the enzyme and substrate.
b) It is a change of secondary structure of the enzyme before binding the substrate.
c) It is a conformational change produced upon binding of the substrate.
d) It is a change in quaternary structure of the enzyme to produce the catalysis.
e) It is the change in the substrate after the catalytic reaction took place.
Topic: Introduction to Enzymes
Section: 24.9
Difficulty Level: Easy
76) Enzymes catalyze stereospecific reactions. Stereospecific reactions are those that:
a) Lead to different stereoisomers from different stereoisomeric substrates.
b) Lead to the same stereoisomer despite starting with different stereoisomeric substrates.
c) Both stereoisomers, cis or trans can produce identical products.
d) Transform different substrates.
e) Transform one conformer into another conformer by rotation of the bonds.
Topic: Introduction to Enzymes
Section: 24.9
Difficulty Level: Medium
77) It is known that enzymes vary considerably in their geometric specificity because:
a) All enzymes bind only one compound as substrate.
b) All enzymes can bind any type of substrate.
c) Only a few enzymes can bind only one compound as substrate.
d) Some enzymes bind only one compound as substrate but others recognize a range of compounds with similar chemical groups.
e) The enzymes will recognize only one type of geometrical shape in the substrate.
Topic: Introduction to Enzymes
Section: 24.9
Difficulty Level: Medium
78) What is lysozyme?
a) It is a hydrolytic DNA.
b) It is an enzyme that breaches the cell wall of gram-positive bacteria.
c) It is a protein that causes DNA hydrolysis.
d) It is an enzymatic protein contained in the nucleous.
e) It is a protein that can bind and hydrolyze esters.
Topic: Lysozyme
Section: 24.10
Difficulty Level: Easy
79) Which of the following statements are correct:
I) Lysozyme produces hydrolysis of specific acetal linkages in peptidoglycan polymers.
II) Lysozyme binds the cell wall substrate in a cleft within its tertiary structure.
III) Evidence suggests sequential SN2 reactions and a covalent enzyme-substrate intermediate.
IV) One product of the hydrolytic reaction shows inversion of configuration.
V) The entire lysozyme molecule acts as a leaving group in the cleavage reaction.
a) I, II
b) III, IV
c) I, II, III, IV
d) I, II, V
e) All are correct.
Topic: Lysozyme
Section: 24.10
Difficulty Level: Hard
80) A prosthetic group is a
a) peptide chain linked to a protein
b) nonprotein group part of a conjugated protein
c) protein
d) smaller protein part of a bigger one
e) protein unit forming part of a protein
Topic: Protein Structure
Section: 24.12
Difficulty Level: Easy
81) A "conjugated protein" is one which:
a) possesses catalytic properties.
b) is a digestive enzyme.
c) exists largely as an α-helix.
d) contains unsaturated amino acids.
e) contains a nonprotein group as part of the molecule.
Topic: Protein Structure
Section: 24.12
Difficulty Level: Easy
82) Two of the more common ionization techniques for the analysis of biopolymers are:
a) HPLC and MALDI
b) 1H-NMR and IR
c) 1H-NMR and ESI
d) Peptide sequencer and mass spectrometry
e) ESI and MALDI
Topic: Analysis of Polypeptides
Section: 24.13
Difficulty Level: Easy
83) The field that studies all proteins that are expressed at a given time is known as:
a) Genomics
b) Metabolomics
c) Proteomics
d) Gene expression
e) Fingerprinting
Topic: Proteomics
Section: 24.14
Difficulty Level: Easy
Question type: Essay
84) Draw the structure of R-aspartic acid.
Topic: General
Section: 24.1
Difficulty Level: Easy
85) Draw the Fischer projection of a threonine diastereomer, and label the chiral centers as R or S.
Topic: Amino Acid Structure
Section: 24.1
Difficulty Level: Medium
86) What is the configuration on all steric centers in these amino acids:
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
87) How many different combinations can exist for a pentapeptide formed by five different amino acids?
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
88) The amino acid threonine, (2S,3R)-2-amino-3-hydroxybutanoic acid, has two chiral centers. Draw a Fischer projection of threonine and label the chirality centers.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Medium
89) Draw the product of the reaction of GlyCys with H2O2.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.2
Difficulty Level: Medium
90) Draw the structures of ValAla and AlaVal as zwitterions.
Topic: General
Section: 24.2
Difficulty Level: Medium
91) Draw the structures of l-phenylalanine and l-valine in Fischer projection.
Topic: General
Section: 24.2
Difficulty Level: Medium
92) Which of the following structures will show the alanine methyl group more deshielded?
Topic: General
Section: 24.2
Difficulty Level: Hard
93) Using the three-letter code names for amino acids, write the structures of all possible peptides containing these amino acids: Val, Ser, Leu
Val-Ser-Leu Leu-Val-Ser
Ser-Leu-Val Leu-Ser-Val
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
94) The 22 -amino acids can be subdivided into three different types on the basis of the structures of their side chains. These three types are: ___.
Topic: Amino Acid Structure
Section: 24.2
Difficulty Level: Easy
95) Draw the structure of the amino acids corresponding to these three-letter codes:
a) Trp b) Ile c) Cys d) His
Topic: Amino Acids Structure
Section: 24.2
Difficulty Level: Medium
96) The 1H NMR spectrum for valine in D2O is below.
Assign the three major signals that appear in the spectrum.
Why is the proton of the carboxylic acid absent?
The proton of the carboxylic acid is absent because it exchanges with deuterium.
Topic: Amino Acid Structure Analysis
Section: 24.2
Difficulty Level: Hard
97) The 13C NMR spectrum below is for either leucine or isoleucine.
Which of the two amino acids is likely to give this spectrum? Explain.
Topic: Amino Acid Structure Analysis
Section: 24.2
Difficulty Level: Hard
98) The Henderson-Hasselbalch equation shows that the ___ of an acid is the ___ at which the acid is half-neutralized.
Topic: Henderson-Hasselbalch Equation
Section: 24.2
Difficulty Level: Easy
99) What is the isoelectric point?
Topic: General
Section: 24.2
Difficulty Level: Easy
100) The pH at which the concentration of the zwitterionic form (dipolar form) of an amino acid is at its highest and the concentrations of the cationic and anionic forms are equal is called the ___.
Topic: Isoelectric Point
Section: 24.2
Difficulty Level: Easy
101) Draw structures to represent what happens when valine is dissolved in a strongly acidic solution (pH=0).
Topic: Dipolar Ions
Section: 24.2
Difficulty Level: Medium
102) Draw structures to represent what happens when valine is dissolved in a strongly basic solution (pH=14).
Topic: Dipolar Ions
Section: 24.2
Difficulty Level: Medium
103) Draw structures to represent what happens when lysine is dissolved in a strongly acidic solution (pH=0).
Topic: Dipolar Ions
Section: 24.2
Difficulty Level: Medium
104) Draw structures to represent what happens when lysine is dissolved in a strongly basic solution (pH=14).
Topic: Dipolar Ions
Section: 24.2
Difficulty Level: Medium
105) Calculate the pI of an amino acid with the following pKas: pKa1 = 2.2; pKa2 = 9.3; pKa3 = 4.3.
Topic: Isoelectric Point
Section: 24.2
Difficulty Level: Medium
106) Draw the structures of the following amino acids as they would appear in solution of pH = 3.
a) lysine, b) glutamic acid, c) alanine, d) glycine.
Topic: Isoelectric Point and pH
Section: 24.2
Difficulty Level: Medium
107) For the following statements, please answer either true or false:
a) Proteins are high-molecular-weight natural polymers made up largely by combination of various α-amino acids. true/false
b) Amino acids may be classified according to properties as: neutral, basic and acidic. true/false
c) Amino acids may be grouped under a nutritive classification into two categories: essential and nonessential. true/false
d) Amino acids have an isoelectric point. true/false
e) Proteins, when hydrolyzed, yield amino acids and polypeptides. true/false
f) Proteins are easily precipitated, or coagulated, by heat, by acids, and by certain heavy metals. true/false
Topic: General
Section: 24.1 and 24.2
Difficulty Level: Medium
108) Amino acids can be prepared from aldehydes by treatment with ammonia and HCN followed by hydrolysis. This method is known as the ___.
Topic: Strecker Synthesis
Section: 24.3
Difficulty Level: Easy
109) What are the name and the structure of the products A and B? Give the IUPAC for A and the trivial name for B.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
110) Show how a Strecker synthesis might be used to prepare phenylalanine starting from phenylacetaldehyde.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.3
Difficulty Level: Medium
111) Complete the reaction presented below:
Topic: Reactions
Section: 24.3
Difficulty Level: Medium
112) Peptide synthesis has four basic steps. These are: ___.
Topic: Peptide Synthesis
Section: 24.3
Difficulty Level: Medium
113) What is the final product formed when potassium phthalimide is subjected to the following reaction sequence? Give structural details of all significant intermediates, including stereochemistry, as applicable.
Topic: Synthesis and Reactions
Section: 24.3
Difficulty Level: Medium
114) Give the structure of the aldehyde which, upon treatment with HCN and ammonia, followed by heating with aqueous acid, would afford racemic tryptophan. What is this strategy for the synthesis of -amino acids called?
Topic: Strecker Synthesis
Section: 24.3
Difficulty Level: Medium
115) What is the final product formed via the following reaction sequence? Give structural details of all significant intermediates.
Topic: Amino Acid Synthesis
Section: 24.3
Difficulty Level: Medium
116) A reagent that reacts with most amino acids to give an intense purple color is called ___.
Topic: Analysis
Section: 24.4
Difficulty Level: Easy
117) Show the structures of the products obtained on reaction of valine with ninhydrin.
Topic: Synthesis and Reactions of Amino Acids
Section: 24.4
Difficulty Level: Medium
118) What type of column chromatography packing is commonly used to separate amino acids by HPLC?
Topic: Analysis
Section: 24.4
Difficulty Level: Medium
119) The exact sequence of the different -amino acids along the protein chain is called the ___ of the protein.
Topic: Protein Structure
Section: 24.5
Difficulty Level: Easy
120) The most widely used method for identifying the N-terminal amino acid in a peptide chain is called the ___.
Topic: Analysis
Section: 24.5
Difficulty Level: Easy
121) C-Terminal amino acids can be identified through the use of ___.
Topic: Analysis
Section: 24.5
Difficulty Level: Easy
122) Draw the structure of the phenylthiohydantoin product you would obtain by Edman degradation of these peptides. Show the configuration of the chirality center on the heterocycle.
a) H-Ile-Leu-Pro-Phe-OH b) H-Asn-Thr-Ser-Gly-Ala-OH
Topic: Peptide Sequencing, Labeling and Synthesis
Section: 24.5
Difficulty Level: Hard
123) Using the one-letter code names for amino acids, write the structures of all possible peptides containing glycine, threonine and phenylalanine:
Topic: Peptide Sequencing, Labeling and Synthesis
Section: 24.2 and 24.5
Difficulty Level: Medium
124) Draw the structure of the following tripeptide (starting with the N-terminal residue and ending with the C-terminal residue), showing stereochemical details:
Gly-Phe-Met
Topic: Peptide Structure
Section: 24.2 and 24.5
Difficulty Level: Medium
125) Draw the structure of the following tripeptide (starting with the N-terminal residue and ending with the C-terminal residue), showing stereochemical details on chirality centers only:
Ala-Ser-Leu
Topic: Peptide Structure
Section: 24.2 and 24.5
Difficulty Level: Medium
126) Draw the structure of the following tripeptide (starting with the N-terminal residue and ending with the C-terminal residue), showing stereochemical details on chirality centers only :
Val-Trp-Asn
Topic: Peptide Structure
Section: 24.2 and 24.5
Difficulty Level: Medium
127) The hormone that regulates glucose metabolism is called ___. Deficiency of this hormone is the major cause of ___.
Topic: Glucose Metabolism
Section: 24.6
Difficulty Level: Easy
128) Suggest a reasonable strategy for the synthesis of the dipeptide Leu-Phe, using established protocol for peptide synthesis.
Topic: Peptide Synthesis
Section: 24.7
Difficulty Level: Medium
129) Show the steps involved in a synthesis of H-Ala-Val-OH using the Merrifield procedure.
FMOC-NH-Val-COOH + Cl-CH2-polymer → FMOC-NH-Val-COO-CH2-polymer
FMOC-NH-Val-COO-CH2-polymer → NH2-Val-COO-CH2-polymer
FMOC-Ala-COOH + NH2-Val-COO-CH2-polymer → FMOC-Ala-CONH-Val-COO-CH2-polymer
FMOC-Ala-CONH-Val-COO-CH2-polymer → NH2-Ala-CONH-Val-COOH + HO-CH2-polymer
Topic: Peptide Sequencing, Labeling and Synthesis
Section: 24.7
Difficulty Level: Hard
130) Give the definition or an example of the following things:
a) α-amino acid b) dipeptide
c) isoelectric point d) DCC
b) A dipeptide results from linkage of two amino acids via one amide bond.
c) The isoelectric point is the pH value when the amino acid exists in its maximum concentration as the neutral, dipolar zwitterion and the concentration of cations and anions are equal.
d)
Topic: General
Section: 24.1, 24.2 and 24.7
Difficulty Level: Medium
131) The folding of the polyamide chain gives rise to higher levels of complexity called the ___ and ___ of the protein.
Topic: Protein Structure
Section: 24.8
Difficulty Level: Easy
132) The secondary structure of proteins has three basic types of folding patterns. These are:
Topic: Protein Structure
Section: 24.8
Difficulty Level: Easy
133) What is the enzyme that hydrolyzes glycosidic linkages in the peptidoglycan polymer of gram-positive bacterial cell walls?
Topic: Lysozyme
Section: 24.10
Difficulty Level: Easy
134) All reactions that occur in living cells are mediated by biological catalysts called ___. The prevailing hypothesis for enzyme catalysis is called the ___ hypothesis.
Topic: Enzymes
Section: 24.9
Difficulty Level: Easy
135) Give the names of three digestive enzymes secreted by the pancreas.
Topic: Serine Proteases
Section: 24.11
Difficulty Level: Easy
136) One common method of analysis used to measure the approximate molecular weight of a protein is called ___.
Topic: Analysis
Section: 24.13
Difficulty Level: Easy
137) The study of all proteins that are expressed in a cell at a given time is called ___.
Topic: Proteomics
Section: 24.14
Difficulty Level: Easy
138) Which of these amino acids can be described as an l-amino acid?
a) I
b) I, II and IV
c) I and III
d) II and IV
e) III and V
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
139) Which of these amino acids is achiral?
a) I
b) II
c) III
d) IV
e) V
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
140) Which of these amino acids is(are) S amino acid(s)?
a) II and IV
b) IV and V
c) I and II
d) V
e) All of these are S amino acids.
Topic: Stereochemistry
Section: 24.1
Difficulty Level: Medium
141) Which of these amino acids is described as an “essential” amino acid?
a) Phenylalanine
b) Threonine
c) Lysine
d) Isoleucine
e) All of these are “essential” amino acids.
Topic: General
Section: 24.2
Difficulty Level: Easy
142) What would be the predominant form of lysine in water at pH 1?
a) I
b) II
c) III
d) IV
e) V
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
143) The predominant form of aspartic acid in water at pH 14 would be:
a) I
b) II
c) III
d) IV
e) V
Topic: Isoelectric Points and pH
Section: 24.2
Difficulty Level: Easy
144) The primary structure of proteins is derived from:
a) peptide linkages.
b) disulfide linkages.
c) hydrogen bond formation.
d) hydrophobic interactions.
e) acid-base interactions.
Topic: Protein Structure
Section: 24.8
Difficulty Level: Easy
145) What statements is false about enzymes?
I) They are biological catalysts, non-specific, that increase the reaction rate by 1000 times.
II) They are catalysts that increase reaction rates by a factor or 1 million or more.
III) Enzymes are remarkably specific, leading Fischer to formulate a lock-and-key hypothesis.
IV) Enzymes undergo an induced fit upon binding the substrate.
V) Enzyme and substrate form a complex
a) I
b) II
c) III
d) IV
e) V
Topic: Introduction to Enzymes
Section: 24.9
Difficulty Level: Easy