Question 1

What peptide coupling reagent is most commonly used in solid phase peptide synthesis?

Accepted Answer

dicyclohex

Question 2

What is the one letter symbol of the amino acid below?

Accepted Answer

A)  G 
B)  Q 
C)  W 
D)  T 
E)  F 
A)  G 
B)  Q 
C)  W 
D)  T 
E)  F

Question 3

Which type of protein, globular or fibrous, tends to function primarily as structural parts of an organism?

Accepted Answer

The answer of Which type of protein, globular or fibrous,...

Question 4

Draw the Fischer projection of L-glutamic acid at a pH of 2.

Accepted Answer

The answer of Draw the Fischer projection of L-glutamic acid...

Question 5

How is the enzyme chymotrypsin used in peptide structure determination?

Accepted Answer

Chymotrypsin cleaves the peptide chain a

Question 6

What is the net charge of arginine in a solution of pH 10.0?

Accepted Answer

The answer of What is the net charge of arginine...

Question 7

The H-bonds formed in the tertiary structure of proteins can be differentiated from those formed in secondary structures. What is the major distinguishing factor?

Accepted Answer

A)  The H-bonds in 3° structures are significantly stronger than those found in 2° structures. 
B)  The H-bonds in 3° structures are more random than those formed in 2° structures. 
C)  The H-bonds in 3° structures are formed by predictable interactions among the peptide backbone α-amine and α-carboxylate groups. 
D)  The H-bonds in 3∘ structures are formed by interactions involving the side chain R-groups. 
E)  Both B and D are correct. 
A)  The H-bonds in 3° structures are significantly stronger than those found in 2° structures. 
B)  The H-bonds in 3° structures are more random than those formed in 2° structures. 
C)  The H-bonds in 3° structures are formed by predictable interactions among the peptide backbone α-amine and α-carboxylate groups. 
D)  The H-bonds in 3∘ structures are formed by interactions involving the side chain R-groups. 
E)  Both B and D are correct.

Question 8

Provide the structure of the predominant form of L-leucine present in an aqueous solution at pH 2.

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 9

Show all organic products when ninhydrin reacts with histidine.

Accepted Answer

The answer of Show all organic products when ninhydrin reacts...

Question 10

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

Question 11

All proteins have a quarternary structure.

Accepted Answer

A) True 
 B)False

Question 12

Which amino acid has an amide group in its side chain?

Accepted Answer

A)  tyrosine 
B)  tryptophan 
C)  isoleucine 
D)  asparagine 
E)  histidine 
A)  tyrosine 
B)  tryptophan 
C)  isoleucine 
D)  asparagine 
E)  histidine

Question 13

Which of the following reagents can be used to convert disulfide bridges into cysteic acid residues?

Accepted Answer

A)  HCO3H 
B)  Zn, HCl 
C)  PhNCS 
D)  PhCH2OCOCl 
E)  CH3I  
A)  HCO3H 
B)  Zn, HCl 
C)  PhNCS 
D)  PhCH2OCOCl 
E)  CH3I

Question 14

Which amino acid has an imidazole ring in its side chain?

Accepted Answer

A)  tyrosine 
B)  tryptophan 
C)  isoleucine 
D)  asparagine 
E)  histidine 
A)  tyrosine 
B)  tryptophan 
C)  isoleucine 
D)  asparagine 
E)  histidine

Question 15

A protein bonded to a fat would be classified as a ________.

Accepted Answer

A)  simple protein 
B)  glycoprotein 
C)  lipoprotein 
D)  metalloprotein 
E)  nucleoprotein 
A)  simple protein 
B)  glycoprotein 
C)  lipoprotein 
D)  metalloprotein 
E)  nucleoprotein

Question 16

Provide the Fischer projection of L-aspartic acid.

Accepted Answer

The answer of Provide the Fischer projection of L-aspartic acid....

Question 17

The primary structure of a protein refers to ________.

Accepted Answer

A)  the sequence of its amino acids 
B)  the orientation of α-helices 
C)  the orientation of pleated sheets 
D)  the orientation of peptide subunits within a complex protein 
E)  the placement of the protein's active site 
A)  the sequence of its amino acids 
B)  the orientation of α-helices 
C)  the orientation of pleated sheets 
D)  the orientation of peptide subunits within a complex protein 
E)  the placement of the protein's active site

Question 18

Provide the structure of the predominant form of glutamine present in an aqueous solution at a pH of 12.0.

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 19

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

Accepted Answer

The aspartic acid side chain is negative

Question 20

In biosynthesis, which amino acid serves as the source of the amino group for other amino acids?

Accepted Answer

A)  D-phenylalanine 
B)  L-phenylalanine 
C)  racemic phenylalanine 
D)  L-glutamic acid 
E)  D-glutamic acid 
A)  D-phenylalanine 
B)  L-phenylalanine 
C)  racemic phenylalanine 
D)  L-glutamic acid 
E)  D-glutamic acid

Exam 24: Amino Acids, Peptides, and Proteins

What peptide coupling reagent is most commonly used in solid phase peptide synthesis?

What is the one letter symbol of the amino acid below?

Which type of protein, globular or fibrous, tends to function primarily as structural parts of an organism?

Draw the Fischer projection of L-glutamic acid at a pH of 2.

How is the enzyme chymotrypsin used in peptide structure determination?

What is the net charge of arginine in a solution of pH 10.0?

The H-bonds formed in the tertiary structure of proteins can be differentiated from those formed in secondary structures. What is the major distinguishing factor?

Provide the structure of the predominant form of L-leucine present in an aqueous solution at pH 2.

Show all organic products when ninhydrin reacts with histidine.

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

All proteins have a quarternary structure.

Which amino acid has an amide group in its side chain?

Which of the following reagents can be used to convert disulfide bridges into cysteic acid residues?

Which amino acid has an imidazole ring in its side chain?

A protein bonded to a fat would be classified as a ________.

Provide the Fischer projection of L-aspartic acid.

The primary structure of a protein refers to ________.

Provide the structure of the predominant form of glutamine present in an aqueous solution at a pH of 12.0.

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

In biosynthesis, which amino acid serves as the source of the amino group for other amino acids?

Structure and Bonding

Acids and Bases; Functional Groups

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides; Nucleophilic Substitution

Structure and Synthesis of Alkenes; Elimination

Reactions of Alkenes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Nuclear Magnetic Resonance Spectroscopy

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Lipids

Synthetic Polymers

Filters