Question 1

Which of the following correctly describes peptide bonds?

Accepted Answer

A)  They are special type of amide bond. 
B)  They are a very stable bonds. 
C)  They are formed when water is split out from an amino group and a carboxylic acid. 
D)  They are a bond which displays resonance. 
E)  All of these 
A)  They are special type of amide bond. 
B)  They are a very stable bonds. 
C)  They are formed when water is split out from an amino group and a carboxylic acid. 
D)  They are a bond which displays resonance. 
E)  All of these E

Question 2

An inhibitor of this type of enzyme will likely act as an antidepressant:

Accepted Answer

A)  Decarboxylases 
B)  Hydrolases 
C)  Monoamine Oxidases 
D)  Exopeptidases 
E)  Inhibiting any of these enzymes can have an antidepressant effect. 
A)  Decarboxylases 
B)  Hydrolases 
C)  Monoamine Oxidases 
D)  Exopeptidases 
E)  Inhibiting any of these enzymes can have an antidepressant effect. C

Question 3

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 E

Question 4

The following molecules are all short peptides except:

Accepted Answer

A)  b-alanine 
B)  Aspartame 
C)  Met-Enkephalin 
D)  Glutathione 
E)  Oxytocin 
A)  b-alanine 
B)  Aspartame 
C)  Met-Enkephalin 
D)  Glutathione 
E)  Oxytocin

Question 5

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 6

Exhibit 3A (for this chapter)   Refer to Exhibit 3A.Which one has a pI of 5.0?

Accepted Answer

A)  Alanine 
B)  Arginine 
C)  Histidine 
D)  Cysteine 
E)  Glutamic acid 
A)  Alanine 
B)  Arginine 
C)  Histidine 
D)  Cysteine 
E)  Glutamic acid

Question 7

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

Question 8

Exhibit 3B   A titration curve.
Refer to Exhibit 3B.The point labeled #1 represents:

Accepted Answer

A)  The fully protonated form 
B)  The pH with maximum negative charge 
C)  The end point of titration with base (OH-) 
D)  The pI of the amino acid 
E)  None of these 
A)  The fully protonated form 
B)  The pH with maximum negative charge 
C)  The end point of titration with base (OH-) 
D)  The pI of the amino acid 
E)  None of these

Question 9

Which amino acid is often added to other molecules to increase their water solubility?

Accepted Answer

A)  Ala 
B)  Asp 
C)  Gly 
D)  Pro 
E)  Trp 
A)  Ala 
B)  Asp 
C)  Gly 
D)  Pro 
E)  Trp

Question 10

Exhibit 3B   A titration curve.
Refer to Exhibit 3B.Which point most likely represents the pK for the carboxyl group?

Accepted Answer

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

Question 11

Oxytocin and vasopressin

Accepted Answer

A)  differ from each other by a single amino acid 
B)  do not contain sulfur 
C)  are peptide hormones 
D)  are tripeptides 
A)  differ from each other by a single amino acid 
B)  do not contain sulfur 
C)  are peptide hormones 
D)  are tripeptides

Question 12

What is the charge on the tetrapeptide lys-lys-his-glu at pH 7?

Accepted Answer

A)  0 
B)  +1 
C)  +2 
D)  -1 
A)  0 
B)  +1 
C)  +2 
D)  -1

Question 13

Which amino acid has the three-letter symbol asn?

Accepted Answer

A)  aspartic acid 
B)  asparagine 
C)  alanine 
D)  arginine 
A)  aspartic acid 
B)  asparagine 
C)  alanine 
D)  arginine

Question 14

Exhibit 3A (for this chapter)   Refer to Exhibit 3A.The pI of the peptide ALA-GLN-ARG-SER-HIS would be:

Accepted Answer

A)  Strongly acid 
B)  Weakly acid (4-6) 
C)  About neutral (6-8) 
D)  Weakly basic (8-10) 
E)  Strongly basic 
A)  Strongly acid 
B)  Weakly acid (4-6) 
C)  About neutral (6-8) 
D)  Weakly basic (8-10) 
E)  Strongly basic

Question 15

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 16

Exhibit 3A (for this chapter)   Refer to Exhibit 3A.Which one has the R-group with the highest pK?

Accepted Answer

A)  Alanine 
B)  Arginine 
C)  Histidine 
D)  Cysteine 
E)  Aspartic Acid 
A)  Alanine 
B)  Arginine 
C)  Histidine 
D)  Cysteine 
E)  Aspartic Acid

Question 17

Which amino acids would migrate furthest toward the anode (positive electrode) during electrophoresis?

Accepted Answer

A)  Aspartic acid. 
B)  Arginine. 
C)  Tyrosine. 
D)  Histidine. 
E)  Glutamine. 
A)  Aspartic acid. 
B)  Arginine. 
C)  Tyrosine. 
D)  Histidine. 
E)  Glutamine.

Question 18

The amino acids which occur in proteins

Accepted Answer

A)  are all of the L- form. 
B)  are all of the D- form. 
C)  can be either the L- or D- form. 
D)  do not have L- and D- forms. 
A)  are all of the L- form. 
B)  are all of the D- form. 
C)  can be either the L- or D- form. 
D)  do not have L- and D- forms.

Question 19

Exhibit 3A (for this chapter)   Refer to Exhibit 3A.The pI of an amino acid is the pH at which it has a zero net charge.What is the increasing order of isoelectric points (low pH to high) for these three amino acids?

Accepted Answer

A)  ALA, HIS, ASP 
B)  ASP, ALA, HIS 
C)  HIS, ALA, ASP 
D)  ALA, ASL, HIS 
E)  ASP, HIS, ALA 
A)  ALA, HIS, ASP 
B)  ASP, ALA, HIS 
C)  HIS, ALA, ASP 
D)  ALA, ASL, HIS 
E)  ASP, HIS, ALA

Question 20

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

Exam 3: Amino Acids and Peptides

Which of the following correctly describes peptide bonds?

An inhibitor of this type of enzyme will likely act as an antidepressant:

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

The following molecules are all short peptides except:

The peptide bond

Exhibit 3A (for this chapter) Refer to Exhibit 3A.Which one has a pI of 5.0?

Which amino acids contain sulfur?

Exhibit 3B A titration curve. Refer to Exhibit 3B.The point labeled #1 represents:

Which amino acid is often added to other molecules to increase their water solubility?

Exhibit 3B A titration curve. Refer to Exhibit 3B.Which point most likely represents the pK for the carboxyl group?

Oxytocin and vasopressin

What is the charge on the tetrapeptide lys-lys-his-glu at pH 7?

Which amino acid has the three-letter symbol asn?

Exhibit 3A (for this chapter) Refer to Exhibit 3A.The pI of the peptide ALA-GLN-ARG-SER-HIS would be:

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

Exhibit 3A (for this chapter) Refer to Exhibit 3A.Which one has the R-group with the highest pK?

Which amino acids would migrate furthest toward the anode (positive electrode) during electrophoresis?

The amino acids which occur in proteins

Exhibit 3A (for this chapter) Refer to Exhibit 3A.The pI of an amino acid is the pH at which it has a zero net charge.What is the increasing order of isoelectric points (low pH to high) for these three amino acids?

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

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

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