Question 1

Which of the following amino acids has a net charge of +1 at pH 4 and a net charge of 0 at pH 8?

Accepted Answer

A)  glu 
B)  arg 
C)  his 
D)  tyr 
A)  glu 
B)  arg 
C)  his 
D)  tyr

Question 2

The amino and carboxyl groups of amino acids are bonded to which carbon?

Accepted Answer

A)  Both are bonded to the α-carbon. 
B)  Both are bonded to the β-carbon. 
C)  The amino is bonded to the α-carbon, and the carboxyl is bonded to the β-carbon. 
D)  The amino is bonded to the β-carbon, and the carboxyl is bonded to the α-carbon. 
A)  Both are bonded to the α-carbon. 
B)  Both are bonded to the β-carbon. 
C)  The amino is bonded to the α-carbon, and the carboxyl is bonded to the β-carbon. 
D)  The amino is bonded to the β-carbon, and the carboxyl is bonded to the α-carbon.

Question 3

This amino acid displays a free amino group in the peptide ALA-GLN-ARG-SER-HIS:

Accepted Answer

A)  ALA 
B)  GLN 
C)  SER 
D)  HIS 
A)  ALA 
B)  GLN 
C)  SER 
D)  HIS

Question 4

Exhibit 3B A titration curve.
  
-Refer to Exhibit 3B. At which point would the amino acid have its maximum negative charge?

Accepted Answer

A)  1 
B)  2 
C)  4 
D)  6 
E)  7 
A)  1 
B)  2 
C)  4 
D)  6 
E)  7

Question 5

Thr and Ser both have hydroxyls as side chains.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following is an amino acid not found in proteins?

Accepted Answer

A)  asparagine 
B)  ornithine 
C)  isoleucine 
D)  proline 
A)  asparagine 
B)  ornithine 
C)  isoleucine 
D)  proline

Question 7

The pKa values of the side chains of the common amino acids

Accepted Answer

A)  are always at low pH 
B)  are always at high pH 
C)  depend on the chemical nature of the side chain 
D)  are not known 
A)  are always at low pH 
B)  are always at high pH 
C)  depend on the chemical nature of the side chain 
D)  are not known

Question 8

Which is a correct pair of abbreviations for an amino acid?

Accepted Answer

A)  Gln / N 
B)  Tyr / T 
C)  Asn / N 
D)  Phe / P 
E)  Pro / Q 
A)  Gln / N 
B)  Tyr / T 
C)  Asn / N 
D)  Phe / P 
E)  Pro / Q

Question 9

Which amino acid takes on a positive charge when the R-group gains a proton?

Accepted Answer

A)  Glutamic Acid 
B)  Histidine 
C)  Glutamine 
D)  Tyrosine 
E)  Glycine 
A)  Glutamic Acid 
B)  Histidine 
C)  Glutamine 
D)  Tyrosine 
E)  Glycine

Question 10

Which of the following is the most similar between oxytocin and vasopressin?

Accepted Answer

A)  their biological function 
B)  their amino acid sequences 
C)  their isoelectric point 
D)  their overall structure 
A)  their biological function 
B)  their amino acid sequences 
C)  their isoelectric point 
D)  their overall structure

Question 11

The pKa values of the alpha carboxyl groups of common amino acids are around

Accepted Answer

A)  pH 2 
B)  pH 5 
C)  pH 7 
D)  pH 9 
A)  pH 2 
B)  pH 5 
C)  pH 7 
D)  pH 9

Question 12

The absolute configuration of amino acids are denoted by their relationship to the L- or D- forms of

Accepted Answer

A)  glyceraldehyde 
B)  glucose 
C)  tartaric acid 
D)  alanine 
A)  glyceraldehyde 
B)  glucose 
C)  tartaric acid 
D)  alanine

Question 13

Which amino acid takes on a negative charge when the R-group loses a proton?

Accepted Answer

A)  Glutamic Acid 
B)  Histidine 
C)  Glutamine 
D)  Tyrosine 
E)  Glutamic Acid and Tyrosine 
A)  Glutamic Acid 
B)  Histidine 
C)  Glutamine 
D)  Tyrosine 
E)  Glutamic Acid and Tyrosine

Question 14

Which of the following has no L or D configuration?

Accepted Answer

A)  Glyceraldehyde 
B)  Proline 
C)  Glycine 
D)  All of these have an L or D configuration 
A)  Glyceraldehyde 
B)  Proline 
C)  Glycine 
D)  All of these have an L or D configuration

Question 15

Which amino acid is classified as polar?

Accepted Answer

A)  L 
B)  H 
C)  P 
D)  I 
A)  L 
B)  H 
C)  P 
D)  I

Question 16

The net charge on the peptide abbreviated CAKE in a solution at pH 7 is closest to

Accepted Answer

A)  −2 
B)  −1. 
C)  0. 
D)  +1. 
A)  −2 
B)  −1. 
C)  0. 
D)  +1.

Question 17

The peptide bond

Accepted Answer

A)  is formed by elimination of water between two amino groups in an amindo acid 
B)  limits the possible orientations of the peptide backbone in a protein 
C)  has acidic and basic characteristics 
D)  all of these 
A)  is formed by elimination of water between two amino groups in an amindo acid 
B)  limits the possible orientations of the peptide backbone in a protein 
C)  has acidic and basic characteristics 
D)  all of these

Question 18

Which of the following is true about uncommon amino acids?

Accepted Answer

A)  They are found in all proteins 
B)  When they are found in proteins, they are first created by modification of the parent amino acid and then incorporated into the protein 
C)  They are formed in the protein by post-translational modification of the parent amino acid 
D)  They are always based on modification of tyrosine 
E)  none of the choices 
A)  They are found in all proteins 
B)  When they are found in proteins, they are first created by modification of the parent amino acid and then incorporated into the protein 
C)  They are formed in the protein by post-translational modification of the parent amino acid 
D)  They are always based on modification of tyrosine 
E)  none of the choices

Question 19

Which group consists only of amino acids with carboxylate side chains?

Accepted Answer

A)  glutamate and cysteine 
B)  aspartate and glycine 
C)  glutamate and lysine 
D)  aspartate and glutamate 
A)  glutamate and cysteine 
B)  aspartate and glycine 
C)  glutamate and lysine 
D)  aspartate and glutamate

Question 20

Which amino acids contain sulfur?

Accepted Answer

A)  cysteine and lysine 
B)  cysteine and methionine 
C)  arginine and methionine 
D)  cysteine and isoleucine 
A)  cysteine and lysine 
B)  cysteine and methionine 
C)  arginine and methionine 
D)  cysteine and isoleucine

Exam 3: Amino Acids and Peptides

Which of the following amino acids has a net charge of +1 at pH 4 and a net charge of 0 at pH 8?

The amino and carboxyl groups of amino acids are bonded to which carbon?

This amino acid displays a free amino group in the peptide ALA-GLN-ARG-SER-HIS:

Exhibit 3B A titration curve. -Refer to Exhibit 3B. At which point would the amino acid have its maximum negative charge?

Thr and Ser both have hydroxyls as side chains.

Which of the following is an amino acid not found in proteins?

The pKa values of the side chains of the common amino acids

Which is a correct pair of abbreviations for an amino acid?

Which amino acid takes on a positive charge when the R-group gains a proton?

Which of the following is the most similar between oxytocin and vasopressin?

The pKa values of the alpha carboxyl groups of common amino acids are around

The absolute configuration of amino acids are denoted by their relationship to the L- or D- forms of

Which amino acid takes on a negative charge when the R-group loses a proton?

Which of the following has no L or D configuration?

Which amino acid is classified as polar?

The net charge on the peptide abbreviated CAKE in a solution at pH 7 is closest to

The peptide bond

Which of the following is true about uncommon amino acids?

Which group consists only of amino acids with carboxylate side chains?

Which amino acids contain sulfur?

Biochemistry and the Organization of Cells

Water: the Solvent for Biochemical Reactions

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of RNA

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

Filters

The pK_a values of the side chains of the common amino acids

The pK_a values of the alpha carboxyl groups of common amino acids are around