Question 1

Provide the structure of the tripeptide glu-ser-ala at pH 2.

Accepted Answer

The answer of Provide the structure of the tripeptide glu-ser-ala...

Question 2

Rank the following amino acids in order of time of elution from a cation-exchange resin and a buffer pH of 4.0: aspartic acid,phenylalanine,arginine,and alanine.

Accepted Answer

aspartic acid > alan...

Question 3

Phenyl isothiocyanate (PITC) is commonly known as Edman's reagent.Edman's reagent is widely used to identify which of the following?

Accepted Answer

A)  the number and kind of amino acids in the protein
B)  the disulfide bridges in the protein
C)  C-terminal amino acid of the protein
D)  N-terminal amino acid of the protein
E)  the number of peptide bonds in the protein

Question 4

What is the major force responsible for the formation of an α-helix in protein secondary structure?

Accepted Answer

The answer of What is the major force responsible for...

Question 5

Give the pH at which histidine exists in the following form.

Accepted Answer

A)  0
B)  4
C)  8
D)  12
E)  14

Question 6

Give the product for the following reaction.

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 7

In a globular protein,would the side chain of isoleucine most probably be oriented toward the interior of the protein or outward toward the aqueous surroundings? Explain.

Accepted Answer

The isoleucine side chain is a nonpolar ...

Question 8

What is electrophoresis?

Accepted Answer

A)  a technique that separates amino acids on the basis of their polarity
B)  a technique that separates amino acids on the basis of their solubility in water
C)  a technique that separates amino acids on the basis of their pI values
D)  a technique that separates amino acids on the basis of pKa of α-COOH values
E)  a technique that separates amino acids on the basis of pKa of α-+NH3 values

Question 9

Give the product for the following reaction.

Accepted Answer

A)  alanine
B)  leucine
C)  valine
D)  isoleucine
E)  glycine

Question 10

What is the major organic product of the following reaction?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 11

Draw structures for the forms of glycine present in basic,neutral,and acidic solutions.

Accepted Answer

+ + H₂N-CH₂-COO- H₃N-CH...

Question 12

Which of the following may characterize the secondary structure of proteins?

Accepted Answer

A)  conformation of the protein backbone
B)  α-Helix
C)  parallel β-pleated sheet
D)  anti-parallel β-pleated sheet
E)  all of the above

Question 13

Provide the structure of the tripeptide val-gly-ser at biological pH.

Accepted Answer

The answer of Provide the structure of the tripeptide val-gly-ser...

Question 14

Which of the following is an acceptable name for the peptide sequence shown below? Glu-Glu-His-Val-Cys

Accepted Answer

A)  1,2-diglutamylhistidylvalylcysteine
B)  glutamylglutamylhistidylvalylcysteine
C)  1-glutamyl-2-glutamylhistidylvalylcysteine
D)  diglutamylhistidylvalylcysteine
E)  biglutamylhistidylvalylcysteine

Question 15

Draw the form in which glutamate exists at pH = 0.

Accepted Answer

At pH = 0,...

Question 16

How is the enzyme chymotrypsin used in peptide structure determination?

Accepted Answer

Chymotrypsin cleaves the peptide chain a...

Question 17

Which of the following terms best describes the side chain of valine?

Accepted Answer

A)  acidic
B)  basic
C)  charged,polar
D)  uncharged,polar
E)  nonpolar

Question 18

Which labeled bond in the following molecule is known as the peptide bond?

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  5

Question 19

In peptide synthesis,give the use of di-tert-butyl dicarbonate.

Accepted Answer

A)  activates the carboxyl group of an amino acid
B)  protects the carboxyl group of an amino acid
C)  protects the amino group of an amino acid
D)  activates the amino group of an amino acid
E)  removes the protecting group on the N-terminal amino acid

Question 20

What is an amino acid analyzer?

Accepted Answer

An instrument that automates ion-exchang...

Exam 21: Amino Acids,peptides,and Proteins

Give the pH at which histidine exists in the following form.

Correct AnswerverifiedShow Answer

Rank the following amino acids in order of time of elution from a cation-exchange resin and a buffer pH of 4.0: aspartic acid,phenylalanine,arginine,and alanine.

Correct Answerverifiedaspartic acid > alan...View AnswerShow Answer

What is the major force responsible for the formation of an α-helix in protein secondary structure?

Correct AnswerverifiedShow Answer

Provide the structure of the tripeptide val-gly-ser at biological pH.

Correct AnswerverifiedShow Answer

Give the product for the following reaction.

Correct AnswerverifiedShow Answer

Give the product for the following reaction.

Correct AnswerverifiedShow Answer

In peptide synthesis,give the use of di-tert-butyl dicarbonate.

Correct AnswerverifiedShow Answer

Which of the following is an acceptable name for the peptide sequence shown below? Glu-Glu-His-Val-Cys

Correct AnswerverifiedShow Answer

What is an amino acid analyzer?

Correct AnswerverifiedAn instrument that automates ion-exchang...View AnswerShow Answer

How is the enzyme chymotrypsin used in peptide structure determination?

Correct AnswerverifiedChymotrypsin cleaves the peptide chain a...View AnswerShow Answer

Provide the structure of the tripeptide glu-ser-ala at pH 2.

Correct AnswerverifiedShow Answer

Which labeled bond in the following molecule is known as the peptide bond?

Correct AnswerverifiedShow Answer

Draw the form in which glutamate exists at pH = 0.

Correct AnswerverifiedAt pH = 0,...View AnswerShow Answer

Which of the following terms best describes the side chain of valine?

Correct AnswerverifiedShow Answer

What is the major organic product of the following reaction?

Correct AnswerverifiedShow Answer

Phenyl isothiocyanate (PITC) is commonly known as Edman's reagent.Edman's reagent is widely used to identify which of the following?

Correct AnswerverifiedShow Answer

In a globular protein,would the side chain of isoleucine most probably be oriented toward the interior of the protein or outward toward the aqueous surroundings? Explain.

Correct AnswerverifiedThe isoleucine side chain is a nonpolar ...View AnswerShow Answer

Which of the following may characterize the secondary structure of proteins?

Correct AnswerverifiedShow Answer

What is electrophoresis?

Correct AnswerverifiedShow Answer

Draw structures for the forms of glycine present in basic,neutral,and acidic solutions.

Correct Answerverified+ + H2N-CH2-COO- H3N-CH...View AnswerShow Answer

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aspartic acid > alan...
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An instrument that automates ion-exchang...
View Answer

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Chymotrypsin cleaves the peptide chain a...
View Answer

Correct Answer
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At pH = 0,...
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The isoleucine side chain is a nonpolar ...
View Answer

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+ + H₂N-CH₂-COO- H₃N-CH...
View Answer