Question 1

Complete the reaction presented below:

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Question 2

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.

Accepted Answer

The answer of The amino acid threonine,(2S,3R)-2-amino-3-hydroxybutanoic acid,has two chiral...

Question 3

What is the pI of the following amino acid?

Accepted Answer

A) 12.0 
B) 3.6 
C) 4.8 
D) 6.0 
E) 7.2

Question 4

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

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Question 5

What product(s)would you expect from the following reaction?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V

Question 6

Which of the following sets of amino acids are essential amino acids:

Accepted Answer

A) Lysine,glutamic acid,asparagine. 
B) Phenylalanine,threonine,lysine. 
C) Threonine,tyrosine,tryptophan. 
D) Proline,cysteine,hydroxyproline. 
E) Arginine,histidine,lysine.

Question 7

Pipecolic acid logically would be substituted for which natural amino acid in the synthesis of peptide analogs?

Accepted Answer

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

Question 8

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.

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Question 9

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

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V

Question 10

A prosthetic group is a

Accepted Answer

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

Question 11

It is known that enzymes vary considerably in their geometric specificity because:

Accepted Answer

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.

Question 12

What is lysozyme?

Accepted Answer

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.

Question 13

Give the definition or an example of the following things:
a)α-amino acid
b)dipeptide
c)isoelectric point
d)DCC

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Question 14

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

Accepted Answer

A) end point. 
B) equivalence point. 
C) neutral point. 
D) isoelectric point. 
E) dipolar point.

Question 15

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

Accepted Answer

A) Leucine 
B) Valine 
C) Glycine 
D) Phenylalanine 
E) Isoleucine

Exam 24: Amino Acids and Proteins