Question 1

Which of these natural amino acids contains an -OH group?

Accepted Answer

A)   Serine
B)   Threonine
C)   Tyrosine
D)   Two of these
E)   All of theseF) A) and B)
G) C) and D)

Question 2

A reagent that reacts with most amino acids to give an intense purple color is called ___________.

Accepted Answer

The answer of A reagent that reacts with most amino...

Question 3

Suggest a reasonable strategy for the synthesis of the dipeptide Leu-Phe,using established protocol for peptide synthesis.

Accepted Answer

The answer of Suggest a reasonable strategy for the synthesis...

Question 4

The purple color of the anion formed in the ninhydrin test for α-amino acids is due to:

Accepted Answer

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.F) B) and E)
G) B) and D)

Question 5

Which of the following amino acids is theoretically capable of existing in diastereomeric forms?

Accepted Answer

A)   I
B)   II
C)   III
D)   IV
E)   VF) C) and D)
G) A) and B)

Question 6

C-terminal amino acids can be identified through the use of _____________.

Accepted Answer

digestive ...

Question 7

Draw the structures of the predominant forms of glycine at pH = 2.0,6.0,and 10.Indicate the direction of migration (toward anode or cathode)for each structure.

Accepted Answer

The answer of Draw the structures of the predominant forms...

Question 8

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

Accepted Answer

The answer of Draw the structure of the following tripeptide...

Question 9

Which amino acid would have its isoelectric point near pH 10?

Accepted Answer

A)   Glycine
B)   Tryptophan
C)   Serine
D)   Proline
E)   LysineF) All of the above
G) A) and D)

Question 10

Which of these natural amino acids,when present in a polypeptide,is likely to exhibit significant hydrogen bonding through its side chain?

Accepted Answer

A)   Serine
B)   Threonine
C)   Tyrosine
D)   Two of these
E)   All of theseF) C) and D)
G) B) and E)

Question 11

Which of these amino acids is a D amino acid?

Accepted Answer

A)   I
B)   II
C)   III
D)   IV
E)   VF) B) and D)
G) C) and E)

Question 12

What is the final product formed via the following reaction sequence? Give structural details of all significant intermediates.

Accepted Answer

The answer of What is the final product formed via...

Question 13

Which of these natural amino acids contains two carboxylic acid groups?

Accepted Answer

A)   Cystine
B)   Cysteine
C)   Glutamic acid
D)   A and B
E)   A and CF) A) and B)
G) A) and E)

Question 14

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?

Accepted Answer

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·AspF) A) and B)
G) C) and D)

Question 15

Disulfide bonds in proteins:

Accepted Answer

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 the aboveF) B) and D)
G) A) and E)

Question 16

Which of these natural amino acids contains a phenolic group?

Accepted Answer

A)   Phenylalanine
B)   Tyrosine
C)   Tryptophan
D)   4-Hydroxyproline
E)   SerineF) A) and D)
G) D) and E)

Question 17

Which is an isolable intermediate in the Strecker synthesis of an amino acid?

Accepted Answer

A)   I
B)   II
C)   III
D)   IV
E)   VF) B) and D)
G) All of the above

Question 18

The secondary structure of proteins has three basic types of folding patterns.These are:

Accepted Answer

-helices,

-...

Question 19

Draw the structure of L-phenylalanine and L-valine in Fischer projection.

Accepted Answer

The answer of Draw the structure of L-phenylalanine and L-valine...

Question 20

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

Accepted Answer

A)   Disulfide linkages
B)   Hydrogen bonds
C)   van der Waals forces
D)   Hydrophobic interactions
E)   All of theseF) A) and E)
G) D) and E)

Exam 24: Amino Acids and Proteins

Draw the structure of L-phenylalanine and L-valine in Fischer projection.

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A reagent that reacts with most amino acids to give an intense purple color is called ___________.

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C-terminal amino acids can be identified through the use of _____________.

Correct Answerverifieddigestive ...View AnswerShow Answer

The purple color of the anion formed in the ninhydrin test for α-amino acids is due to:

Correct AnswerverifiedShow Answer

Which of these natural amino acids contains an -OH group?

Correct AnswerverifiedShow Answer

Which of the following amino acids is theoretically capable of existing in diastereomeric forms?

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Which of these amino acids is a D amino acid?

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Which of these natural amino acids contains two carboxylic acid groups?

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Which amino acid would have its isoelectric point near pH 10?

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The secondary structure of proteins has three basic types of folding patterns.These are:

Correct Answerverified-helices,-...View AnswerShow Answer

Disulfide bonds in proteins:

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

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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

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Which of these natural amino acids contains a phenolic group?

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Which of these natural amino acids,when present in a polypeptide,is likely to exhibit significant hydrogen bonding through its side chain?

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Suggest a reasonable strategy for the synthesis of the dipeptide Leu-Phe,using established protocol for peptide synthesis.

Correct AnswerverifiedShow Answer

Which is an isolable intermediate in the Strecker synthesis of an amino acid?

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What is the final product formed via the following reaction sequence? Give structural details of all significant intermediates.

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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?

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Draw the structures of the predominant forms of glycine at pH = 2.0,6.0,and 10.Indicate the direction of migration (toward anode or cathode)for each structure.

Correct AnswerverifiedShow Answer

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digestive ...
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-helices,-...
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