Question 1

Which of the amino acids represented below has two chiral centers?

Accepted Answer

A)  Ala
B)  Leu
C)  Ile
D)  Pro
E)  AsnF) B) and E)
G) A) and B)

Question 2

Matching
-In the tripeptide Lys─Pro─Ile, there are ______ charged groups at pH 7.

Accepted Answer

A)  glutamate
B)  uncharged
C)  deprotonated
D)  three
E)  amino groupF) twoG) C-terminusH) lysineI) racemic mixtureJ) cysteineK) zeroL) protonatedM) isoleucineN) tryptophanO) phenylalanineP) N-terminusQ) G) and N)
R) F) and H)

Question 3

the diagram below. 
-What is the name of this molecule?

Accepted Answer

A)  GABA
B)  thyroxine
C)  ( γ\gammaγ -carboxyglutamate) 
D)  glutathione
E)  epinephrine F) A) and B)
G) D) and E) D

Question 4

The peptide AYDG has an N-terminal _________ residue.

Accepted Answer

A)  glycine
B)  glutamic acid
C)  glutamine
D)  aspartic acid
E)  alanineF) None of the above
G) C) and D)

Question 5

Which of the following tripeptides would be expected to be the most hydrophobic?

Accepted Answer

A)  KYG
B)  KYA
C)  GYA
D)  DYA
E)  DYGF) B) and E)
G) A) and E)

Question 6

Which one of the representations describes the oligopeptide shown below?

Accepted Answer

A)  Tyr-Ala-Thr
B)  Tyr-Gly-Cys
C)  Tyr-Ala-Ser
D)  Phe-Gly-Cys
E)  Phe-Ala-ThrF) A) and D)
G) B) and C)

Question 7

The pK1, pK2, and pKR for the amino acid glutamate are 2.1, 9.5, and 4.1, respectively.At pH 11.0, glutamate would be charged predominantly as follows:

Accepted Answer

A)  ( α\alphaα -carboxylate +1,  α\alphaα -amino 0,  γ\gammaγ -carboxylate +1, net charge +2) 
B)  ( α\alphaα -carboxylate −1,  α\alphaα -amino +1,  γ\gammaγ -carboxylate −1, net charge −1) 
C)  ( α\alphaα -carboxylate 0,  α\alphaα -amino 0,  γ\gammaγ -carboxylate 0, net charge 0) 
D)  ( α\alphaα -carboxylate +1,  α\alphaα -amino −1,  γ\gammaγ -carboxylate +1, net charge +1) 
E)  ( α\alphaα -carboxylate −1,  α\alphaα -amino 0,  γ\gammaγ -carboxylate −1, net charge −2)  F) A) and B)
G) B) and E)

Question 8

What percentage of the 20 amino acids is considered to be nutritionally essential to lab animals?

Accepted Answer

A)  0%
B)  25%
C)  50%
D)  75%
E)  100%F) A) and D)
G) C) and D)

Question 9

Matching
-At a pH above its pKa, the phenol group of tyrosine is ______.

Accepted Answer

A)  glutamate
B)  uncharged
C)  deprotonated
D)  three
E)  amino groupF) twoG) C-terminusH) lysineI) racemic mixtureJ) cysteineK) zeroL) protonatedM) isoleucineN) tryptophanO) phenylalanineP) N-terminusQ) A) and B)
R) B) and E)

Question 10

Which of the following amino acids has a sulfur atom in its side chain?

Accepted Answer

A)  Asn
B)  Ser
C)  Phe
D)  Met
E)  TyrF) A) and D)
G) A) and C)

Question 11

Matching
-At a pH below its pKa, the  ε\varepsilonε -amino group of lysine is ______.

Accepted Answer

A)  glutamate
B)  uncharged
C)  deprotonated
D)  three
E)  amino groupF) twoG) C-terminusH) lysineI) racemic mixtureJ) cysteineK) zeroL) protonatedM) isoleucineN) tryptophanO) phenylalanineP) N-terminus Q) B) and L)
R) C) and E)

Question 12

In general, amino acids are chiral molecules that act as building blocks for proteins.In addition, amino acids and amino acid derivative can act as extracellular messenger molecules such as hormones or neurotransmitters.
a.How many different amino acids can be incorporated into proteins during translation?
b.Do ribosomes use L or D amino acids for protein synthesis?
c.Name one amino acid or amino acid derivative that can act as hormone or neurotransmitter.
d.Draw the predominant structure of valine at pH 10 (pKas are 2.3 and 9.7).

Accepted Answer

a.20
b.L
c.glycine, ...

Question 13

All amino acids derived from proteins have the same stereochemical conformation as.

Accepted Answer

A)  L-glyceraldehyde.
B)  (R) -alanine.
C)  D-glucose.
D)  (S) -cysteine.
E)  glycine.F) A) and E)
G) None of the above

Question 14

the diagram shown below. 
-What is the three-letter symbol for the C-terminal amino acid in the peptide shown above?

Accepted Answer

A)  Gly
B)  Asp
C)  Tyr
D)  Met
E)  PheF) D) and E)
G) A) and D) E

Question 15

Which of the following amino acids has an uncharged polar side chain at pH 7.0?

Accepted Answer

A)  Arg
B)  Thr
C)  Glu
D)  Pro
E)  IleF) A) and B)
G) B) and C) B

Question 16

The pK1, pK2, and pKR for the amino acid lysine are 2.2, 9.1, and 10.5, respectively.At pH 1.0, lysine would be charged predominantly as follows:

Accepted Answer

A)  ( α\alphaα -carboxylate 0,  α\alphaα -amino −1,  ε\varepsilonε -amino −1, net charge −2) 
B)  ( α\alphaα -carboxylate −1,  α\alphaα -amino +1,  ε\varepsilonε -amino +1, net charge +1) 
C)  ( α\alphaα -carboxylate +1,  α\alphaα -amino +2,  ε\varepsilonε -amino +2, net charge +5) 
D)  ( α\alphaα -carboxylate 0,  α\alphaα -amino +1,  ε\varepsilonε -amino +1, net charge +2) 
E)  ( α\alphaα -carboxylate +2,  α\alphaα -amino +1,  ε\varepsilonε -amino +1, net charge +4)  F) A) and D)
G) B) and D)

Question 17

The figure below shows the predominant structure of an oligopeptide at pH 7.0.  a.How many amino acids are present in this peptide?
b.Circle one peptide bond in this peptide.
c.Draw a square around one alpha carbon in this peptide
d.The pKas of the ionizable groups in this peptide are 2.0, 4.0, and 9.0.What is the ionic charge of this molecule at pH 1.0
e.What is the name of the N-terminal amino acid in this peptide?

Accepted Answer

a.5
b.

c.

d.The charge of this molecu...

Question 18

the diagram shown below. 
-How many amino acid residues are present in the peptide shown above?

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  5F) A) and C)
G) C) and D)

Question 19

What is the three-letter abbreviation for the peptide valylarginylisoleucine?

Accepted Answer

A)  Val─Arg─Ile
B)  Val─Agn─Leu
C)  Vln─Arg─Ile
D)  Val─Agn─Isl
E)  Vln─Arg─LeuF) A) and C)
G) B) and C)

Question 20

The formation of a dipeptide from two amino acids involves

Accepted Answer

A)  side-chain complementarity.
B)  loss of water.
C)  oxidation of the  α\alphaα -carbon.
D)  reduction of the  α\alphaα -carbon.
E)  base catalysis. F) B) and E)
G) B) and D)

Exam 4: Amino Acids

Which of the amino acids represented below has two chiral centers?

Correct Answer
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Matching -In the tripeptide Lys─Pro─Ile, there are ______ charged groups at pH 7.

Correct Answer
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the diagram below. $the diagram below. -What is the name of this molecule? A) GABA B) thyroxine C) ( \gamma -carboxyglutamate) D) glutathione E) epinephrine$ -What is the name of this molecule?

Correct Answer
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D

The peptide AYDG has an N-terminal _________ residue.

Correct Answer
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Which of the following tripeptides would be expected to be the most hydrophobic?

Correct Answer
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Which one of the representations describes the oligopeptide shown below?

Correct Answer
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The pK₁, pK₂, and pK_R for the amino acid glutamate are 2.1, 9.5, and 4.1, respectively.At pH 11.0, glutamate would be charged predominantly as follows:

Correct Answer
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What percentage of the 20 amino acids is considered to be nutritionally essential to lab animals?

Correct Answer
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Matching -At a pH above its pK_a, the phenol group of tyrosine is ______.

Correct Answer
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Which of the following amino acids has a sulfur atom in its side chain?

Correct Answer
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Matching -At a pH below its pK_a, the $\varepsilon$ -amino group of lysine is ______.

Correct Answer
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Correct Answer
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a.20
b.L
c.glycine, ...
View Answer

All amino acids derived from proteins have the same stereochemical conformation as.

Correct Answer
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the diagram shown below. -What is the three-letter symbol for the C-terminal amino acid in the peptide shown above?

Correct Answer
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E

Which of the following amino acids has an uncharged polar side chain at pH 7.0?

Correct Answer
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B

The pK₁, pK₂, and pK_R for the amino acid lysine are 2.2, 9.1, and 10.5, respectively.At pH 1.0, lysine would be charged predominantly as follows:

Correct Answer
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Correct Answer
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a.5
b.
c.
d.The charge of this molecu...
View Answer

the diagram shown below. -How many amino acid residues are present in the peptide shown above?

Correct Answer
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What is the three-letter abbreviation for the peptide valylarginylisoleucine?

Correct Answer
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The formation of a dipeptide from two amino acids involves

Correct Answer
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Exam 4: Amino Acids

Which of the amino acids represented below has two chiral centers?

Correct AnswerverifiedShow Answer

Matching -In the tripeptide Lys─Pro─Ile, there are ______ charged groups at pH 7.

Correct AnswerverifiedShow Answer

the diagram below. -What is the name of this molecule?

Correct AnswerverifiedD

The peptide AYDG has an N-terminal _________ residue.

Correct AnswerverifiedShow Answer

Which of the following tripeptides would be expected to be the most hydrophobic?

Correct AnswerverifiedShow Answer

Which one of the representations describes the oligopeptide shown below?

Correct AnswerverifiedShow Answer

The pK1, pK2, and pKR for the amino acid glutamate are 2.1, 9.5, and 4.1, respectively.At pH 11.0, glutamate would be charged predominantly as follows:

Correct AnswerverifiedShow Answer

What percentage of the 20 amino acids is considered to be nutritionally essential to lab animals?

Correct AnswerverifiedShow Answer

Matching -At a pH above its pKa, the phenol group of tyrosine is ______.

Correct AnswerverifiedShow Answer

Which of the following amino acids has a sulfur atom in its side chain?

Correct AnswerverifiedShow Answer

Matching -At a pH below its pKa, the ε\varepsilonε -amino group of lysine is ______.

Correct AnswerverifiedShow Answer

Correct Answerverifieda.20b.Lc.glycine, ...View AnswerShow Answer

All amino acids derived from proteins have the same stereochemical conformation as.

Correct AnswerverifiedShow Answer

the diagram shown below. -What is the three-letter symbol for the C-terminal amino acid in the peptide shown above?

Correct AnswerverifiedE

Which of the following amino acids has an uncharged polar side chain at pH 7.0?

Correct AnswerverifiedB

The pK1, pK2, and pKR for the amino acid lysine are 2.2, 9.1, and 10.5, respectively.At pH 1.0, lysine would be charged predominantly as follows:

Correct AnswerverifiedShow Answer

Correct Answerverifieda.5b. c. d.The charge of this molecu...View AnswerShow Answer

the diagram shown below. -How many amino acid residues are present in the peptide shown above?

Correct AnswerverifiedShow Answer

What is the three-letter abbreviation for the peptide valylarginylisoleucine?

Correct AnswerverifiedShow Answer

The formation of a dipeptide from two amino acids involves

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

the diagram below. $the diagram below. -What is the name of this molecule? A) GABA B) thyroxine C) ( \gamma -carboxyglutamate) D) glutathione E) epinephrine$ -What is the name of this molecule?

Correct Answer
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D

Correct Answer
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Correct Answer
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Correct Answer
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The pK₁, pK₂, and pK_R for the amino acid glutamate are 2.1, 9.5, and 4.1, respectively.At pH 11.0, glutamate would be charged predominantly as follows:

Correct Answer
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Correct Answer
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Matching -At a pH above its pK_a, the phenol group of tyrosine is ______.

Correct Answer
verified

Correct Answer
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Matching -At a pH below its pK_a, the $\varepsilon$ -amino group of lysine is ______.

Correct Answer
verified

Correct Answer
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a.20
b.L
c.glycine, ...
View Answer

Correct Answer
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Correct Answer
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E

Correct Answer
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B

The pK₁, pK₂, and pK_R for the amino acid lysine are 2.2, 9.1, and 10.5, respectively.At pH 1.0, lysine would be charged predominantly as follows:

Correct Answer
verified

Correct Answer
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a.5
b.
c.
d.The charge of this molecu...
View Answer

Correct Answer
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Correct Answer
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Correct Answer
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