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Which attractive force is responsible for maintaining the tertiary structure of proteins?


A) Disulfide linkages
B) Hydrogen bonds
C) Salt bridges
D) Hydrophobic interactions
E) All of these

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Nearly all amino acids immediately release N2 gas upon diazotization (treatment with aqueous HCl and sodium nitrite) .Which amino acid would not?


A) Lysine
B) Histidine
C) Tyrosine
D) Cysteine
E) Proline

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Which amino acid is responsible for the condition known as phenylketonuria (PKU) which occurs in a small fraction of the population?


A) Tryptophan
B) Histidine
C) Phenylalanine
D) Proline
E) Valine

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C

Which amino acid does not form a characteristic blue color with ninhydrin?


A) Cysteine
B) Lysine
C) Proline
D) Valine
E) Tryptophan

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Why is the additional (ring) nitrogen in tryptophan not very basic? Why is the additional (ring) nitrogen in tryptophan not very basic? A) Cyclic amines are not basic. B) It is too far from the carboxyl group to be effected. C) Aromatic amines are weakly basic because of resonance. D) The additional amine group is offset by an additional carboxylic acid group. E) It is sp<sup>2</sup> hybridized as therefore not as basic.


A) Cyclic amines are not basic.
B) It is too far from the carboxyl group to be effected.
C) Aromatic amines are weakly basic because of resonance.
D) The additional amine group is offset by an additional carboxylic acid group.
E) It is sp2 hybridized as therefore not as basic.

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The secondary structure of proteins is held together by hydrogen bonds between which protein sub-structures?


A) The C=O and N-H on amino acid side chains
B) The C=O on the protein backbone and the N-H on the amino acid side chains
C) The C=O on the amino acid side chains and the N-H on the protein backbone
D) The C=O and the N-H on the protein backbone
E) There are no hydrogen bonds involved with secondary structure.

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D

What process would one use to make multiple copies of a fragment of DNA?


A) Polymerase chain reaction
B) Electrophoresis
C) Transcription
D) Translation
E) Merrifield solid-phase synthesis

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A

Folding of polypeptides influenced by distant residues is an example of what protein structure?


A) Primary
B) Secondary
C) Tertiary
D) Quaternary
E) None of the above.

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What would be the abbreviated name of the following polypeptide? What would be the abbreviated name of the following polypeptide? A) val-thr-glu-ala-gln B) ala-thr-glu-val-gln C) met-ser-asp-leu-pro-NH<sub>2</sub> D) ala-ser-asp-val-gln E) ala-ser-asp-val-pro-NH<sub>2</sub>


A) val-thr-glu-ala-gln
B) ala-thr-glu-val-gln
C) met-ser-asp-leu-pro-NH2
D) ala-ser-asp-val-gln
E) ala-ser-asp-val-pro-NH2

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What would result from the following reactions? What would result from the following reactions? A) <sup> </sup> B) C) D) E)


A)
What would result from the following reactions? A) <sup> </sup> B) C) D) E)
B)
What would result from the following reactions? A) <sup> </sup> B) C) D) E)
C)
What would result from the following reactions? A) <sup> </sup> B) C) D) E)
D)
What would result from the following reactions? A) <sup> </sup> B) C) D) E)
E)
What would result from the following reactions? A) <sup> </sup> B) C) D) E)

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Which of the following is least likely to be found in nature?


A)
Which of the following is least likely to be found in nature? A) B) C) D) E)
B)
Which of the following is least likely to be found in nature? A) B) C) D) E)
C)
Which of the following is least likely to be found in nature? A) B) C) D) E)
D)
Which of the following is least likely to be found in nature? A) B) C) D) E)
E)
Which of the following is least likely to be found in nature? A) B) C) D) E)

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Which of the following represents how a typical amino acid would mainly exist in basic solution (pH > 7) ?


A)
Which of the following represents how a typical amino acid would mainly exist in basic solution (pH > 7) ? A) B) C) D) E) None of the above.
B)
Which of the following represents how a typical amino acid would mainly exist in basic solution (pH > 7) ? A) B) C) D) E) None of the above.
C)
Which of the following represents how a typical amino acid would mainly exist in basic solution (pH > 7) ? A) B) C) D) E) None of the above.
D)
Which of the following represents how a typical amino acid would mainly exist in basic solution (pH > 7) ? A) B) C) D) E) None of the above.
E) None of the above.

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Why is the following not a good two step route for the preparation of pure L-alanine? Why is the following not a good two step route for the preparation of pure L-alanine? A) The bromination is not selective (the CH<sub>3</sub> and CH<sub>2</sub> groups are both brominated) . B) Ammonia is not sufficiently nucleophillic to react with a secondary bromide. C) Only the CH<sub>3</sub> group is brominated. D) The product will be racemic. E) Propanamide would be the major product.


A) The bromination is not selective (the CH3 and CH2 groups are both brominated) .
B) Ammonia is not sufficiently nucleophillic to react with a secondary bromide.
C) Only the CH3 group is brominated.
D) The product will be racemic.
E) Propanamide would be the major product.

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Which amino acid does not have an enantiomer?


A) Alanine
B) Glutamine
C) Histidine
D) Aspartic acid
E) Glycine

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Chymotrypsin catalyzes hydrolysis of peptide bonds where? Chymotrypsin catalyzes hydrolysis of peptide bonds where? A) At the carboxy end of residues with basic side chains B) At the amino end of residues containing aliphatic residues C) At the carboxy end of residues with aromatic side chains D) At the amino end of residues with aromatic side chains E) At the carboxy end of methionine residues


A) At the carboxy end of residues with basic side chains
B) At the amino end of residues containing aliphatic residues
C) At the carboxy end of residues with aromatic side chains
D) At the amino end of residues with aromatic side chains
E) At the carboxy end of methionine residues

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What is the name of the DNA base shown? What is the name of the DNA base shown? A) Guanine B) Cytosine C) Adenine D) Uracil E) Thymine


A) Guanine
B) Cytosine
C) Adenine
D) Uracil
E) Thymine

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It was not until 1974 that -carboxyglutamic acid (shown below) was discovered (by researchers at the University of Colorado) in polypeptides.Based on your knowledge of organic chemistry,what is the most likely reason that this particular amino acid escaped identification so long? It was not until 1974 that <font face= symbol ></font>-carboxyglutamic acid (shown below) was discovered (by researchers at the University of Colorado) in polypeptides.Based on your knowledge of organic chemistry,what is the most likely reason that this particular amino acid escaped identification so long? A) It tended to spontaneously form a cyclic anhydride: B) It tended to spontaneously lose carbon dioxide: C) It easily underwent a reverse-Knovenagle reaction: D) It tended to spontaneously form a cyclic amide (lactam) : E) It was simply too polar to extract into non-polar organic solvents.


A) It tended to spontaneously form a cyclic anhydride:
It was not until 1974 that <font face= symbol ></font>-carboxyglutamic acid (shown below) was discovered (by researchers at the University of Colorado) in polypeptides.Based on your knowledge of organic chemistry,what is the most likely reason that this particular amino acid escaped identification so long? A) It tended to spontaneously form a cyclic anhydride: B) It tended to spontaneously lose carbon dioxide: C) It easily underwent a reverse-Knovenagle reaction: D) It tended to spontaneously form a cyclic amide (lactam) : E) It was simply too polar to extract into non-polar organic solvents.
B) It tended to spontaneously lose carbon dioxide:
It was not until 1974 that <font face= symbol ></font>-carboxyglutamic acid (shown below) was discovered (by researchers at the University of Colorado) in polypeptides.Based on your knowledge of organic chemistry,what is the most likely reason that this particular amino acid escaped identification so long? A) It tended to spontaneously form a cyclic anhydride: B) It tended to spontaneously lose carbon dioxide: C) It easily underwent a reverse-Knovenagle reaction: D) It tended to spontaneously form a cyclic amide (lactam) : E) It was simply too polar to extract into non-polar organic solvents.
C) It easily underwent a reverse-Knovenagle reaction:
It was not until 1974 that <font face= symbol ></font>-carboxyglutamic acid (shown below) was discovered (by researchers at the University of Colorado) in polypeptides.Based on your knowledge of organic chemistry,what is the most likely reason that this particular amino acid escaped identification so long? A) It tended to spontaneously form a cyclic anhydride: B) It tended to spontaneously lose carbon dioxide: C) It easily underwent a reverse-Knovenagle reaction: D) It tended to spontaneously form a cyclic amide (lactam) : E) It was simply too polar to extract into non-polar organic solvents.
D) It tended to spontaneously form a cyclic amide (lactam) :
It was not until 1974 that <font face= symbol ></font>-carboxyglutamic acid (shown below) was discovered (by researchers at the University of Colorado) in polypeptides.Based on your knowledge of organic chemistry,what is the most likely reason that this particular amino acid escaped identification so long? A) It tended to spontaneously form a cyclic anhydride: B) It tended to spontaneously lose carbon dioxide: C) It easily underwent a reverse-Knovenagle reaction: D) It tended to spontaneously form a cyclic amide (lactam) : E) It was simply too polar to extract into non-polar organic solvents.
E) It was simply too polar to extract into non-polar organic solvents.

Correct Answer

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What is dicyclohexylcarbodiimide (DCC) used for in peptide synthesis?


A) DCC protects the amino group of the intended N-terminal amino acid.
B) DCC activates the carboxyl group toward nucleophillic attack.
C) DCC cleaves the blocking groups from the final peptide.
D) DCC is the resin (solid support) used to anchor the growing polypeptide.
E) DCC removes the peptide from the resin at the conclusion of the synthesis.

Correct Answer

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Amino acids are covalently bonded to each other through_______.


A) hydrogen bonding
B) disulfide bridges
C) peptide bonds
D) ( and folds)
E) None of the above.

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Although traces of racemic amino acids have been found in meteorites,nearly all naturally occurring amino acids on Earth have the stereochemistry shown.What is true of this stereochemistry? (Assume R = alkyl) Although traces of racemic amino acids have been found in meteorites,nearly all naturally occurring amino acids on Earth have the stereochemistry shown.What is true of this stereochemistry? (Assume R = alkyl) A) Amino acids are of the (R) configuration. B) Amino acids are of the (S) configuration. C) Amino acids are not chiral. D) Amino acids are meso compounds. E) Amino acids easily change configuration.


A) Amino acids are of the (R) configuration.
B) Amino acids are of the (S) configuration.
C) Amino acids are not chiral.
D) Amino acids are meso compounds.
E) Amino acids easily change configuration.

Correct Answer

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Showing 1 - 20 of 39

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