Question 1

Which Fischer projections represent naturally-occurring amino acids?

Accepted Answer

A) only structure 1 
B) only structure 2 
C) structures 1, 2, and 3 
D) structures 2 and 3 
A) only structure 1 
B) only structure 2 
C) structures 1, 2, and 3 
D) structures 2 and 3 D

Question 2

The pH at which an amino acid exists primarily in its neutral form is called its _____ point.

Accepted Answer

isoelectric

Question 3

Denaturation of a protein results in the loss of its native conformation and its biological activity. Which statement best describes what happens to a protein when it is denatured?

Accepted Answer

A) Peptide bonds are broken. 
B) New amino acids are joined to the peptide backbone. 
C) Secondary, tertiary, and quaternary levels of structure are disrupted. 
D) The N-terminal and C-terminal ends of the protein are hydrolyzed by enzymes. 
A) Peptide bonds are broken. 
B) New amino acids are joined to the peptide backbone. 
C) Secondary, tertiary, and quaternary levels of structure are disrupted. 
D) The N-terminal and C-terminal ends of the protein are hydrolyzed by enzymes. C

Question 4

_____ bonds between cysteine residues are the only covalent bonds that stabilize the tertiary structure of a protein.

Accepted Answer

The answer of _____ bonds between cysteine residues are the...

Question 5

_____ proteins are composed of long linear polypeptide chains that are bundled together to form rods or sheets that are insoluble in water and serve structural roles.

Accepted Answer

The answer of _____ proteins are composed of long linear...

Question 6

Trypsin is a digestive enzyme that hydrolyzes peptide bonds only when the carbonyl group in the amide bond comes from Lys or Arg. What fragments result when the peptide Gly-Lys-Arg-Ala-Ala-Arg is hydrolyzed by trypsin?

Accepted Answer

A) Gly, Lys, Arg, Ala-Ala, Arg 
B) Gly-Lys, Arg-Ala-Ala, Arg 
C) Gly-Lys, Arg, Ala-Ala, Arg 
A) Gly, Lys, Arg, Ala-Ala, Arg 
B) Gly-Lys, Arg-Ala-Ala, Arg 
C) Gly-Lys, Arg, Ala-Ala, Arg

Question 7

What is the strongest type of interaction between two cysteine amino acid side chains in a protein?

Accepted Answer

A) hydrogen bonding 
B) London dispersion forces 
C) disulfide bond 
D) electrostatic interactions 
A) hydrogen bonding 
B) London dispersion forces 
C) disulfide bond 
D) electrostatic interactions

Question 8

Which conditions are commonly diagnosed by measuring the levels of specific enzymes in the blood?

Accepted Answer

A) heart attack 
B) high blood pressure 
C) pregnancy 
D) migraines 
A) heart attack 
B) high blood pressure 
C) pregnancy 
D) migraines

Question 9

Secretion of vasopressin by the pituitary gland causes the kidneys to retain fluid, resulting in decreased urine output.

Accepted Answer

A) True 
 B)False

Question 10

What is the C-terminal amino acid in the tetrapeptide glycylalanyisoleucylmethionine?

Accepted Answer

A) alanine 
B) glycine 
C) methionine 
D) isoleucine 
A) alanine 
B) glycine 
C) methionine 
D) isoleucine

Question 11

Based on its name, which compound is an enzyme?

Accepted Answer

A) glucose 
B) triosephosphate isomerase 
C) N-acetyl-D-glucosamine 
D) dihydrofolate 
A) glucose 
B) triosephosphate isomerase 
C) N-acetyl-D-glucosamine 
D) dihydrofolate

Question 12

Insulin is a small protein consisting of two polypeptide chains held together by hydrogen bonds.

Accepted Answer

A) True 
 B)False

Question 13

HIV protease inhibitors are used to treat HIV by binding to an enzyme needed by the virus to replicate itself.

Accepted Answer

A) True 
 B)False

Question 14

D-Amino acids have the -NH3+ group on the left side in the Fischer projection.

Accepted Answer

A) True 
 B)False

Question 15

What is the three-letter abbreviation of asparagine?

Accepted Answer

A) Asp 
B) Asg 
C) Asn 
D) Arg 
A) Asp 
B) Asg 
C) Asn 
D) Arg

Question 16

How many chirality centers are in leu-enkephalin (structure shown)?

Accepted Answer

A) 3 
B) 4 
C) 5 
D) 9 
A) 3 
B) 4 
C) 5 
D) 9

Question 17

When the peptide below is hydrolyzed with water, the products are the amino acids proline, cysteine, and glutamine.

Accepted Answer

A) True 
 B)False

Question 18

What is the charge on a zwitterion?

Accepted Answer

A) positive 
B) neutral 
C) negative 
D) The charge or lack of charge varies depending on the amino acid. 
A) positive 
B) neutral 
C) negative 
D) The charge or lack of charge varies depending on the amino acid.

Question 19

Since amino acids contain a base (NH2 group)and an acid (COOH), proton transfer from the acid to the base forms a salt called a/an _____, which contains both a positive and a negative charge.

Accepted Answer

Question 20

The "cartoon" shown is an example of competitive inhibition.

Accepted Answer

A) True 
 B)False

Exam 21: Amino Acids, Proteins, and Enzymes

Which Fischer projections represent naturally-occurring amino acids?

The pH at which an amino acid exists primarily in its neutral form is called its _____ point.

Denaturation of a protein results in the loss of its native conformation and its biological activity. Which statement best describes what happens to a protein when it is denatured?

_____ bonds between cysteine residues are the only covalent bonds that stabilize the tertiary structure of a protein.

_____ proteins are composed of long linear polypeptide chains that are bundled together to form rods or sheets that are insoluble in water and serve structural roles.

Trypsin is a digestive enzyme that hydrolyzes peptide bonds only when the carbonyl group in the amide bond comes from Lys or Arg. What fragments result when the peptide Gly-Lys-Arg-Ala-Ala-Arg is hydrolyzed by trypsin?

What is the strongest type of interaction between two cysteine amino acid side chains in a protein?

Which conditions are commonly diagnosed by measuring the levels of specific enzymes in the blood?

Secretion of vasopressin by the pituitary gland causes the kidneys to retain fluid, resulting in decreased urine output.

What is the C-terminal amino acid in the tetrapeptide glycylalanyisoleucylmethionine?

Based on its name, which compound is an enzyme?

Insulin is a small protein consisting of two polypeptide chains held together by hydrogen bonds.

HIV protease inhibitors are used to treat HIV by binding to an enzyme needed by the virus to replicate itself.

D-Amino acids have the -NH3+ group on the left side in the Fischer projection.

What is the three-letter abbreviation of asparagine?

How many chirality centers are in leu-enkephalin (structure shown)?

When the peptide below is hydrolyzed with water, the products are the amino acids proline, cysteine, and glutamine.

What is the charge on a zwitterion?

Since amino acids contain a base (NH2 group)and an acid (COOH), proton transfer from the acid to the base forms a salt called a/an _____, which contains both a positive and a negative charge.

The "cartoon" shown is an example of competitive inhibition.

Matter and Measurement

Atoms and the Periodic Table

Ionic Compounds

Covalent Compounds

Chemical Reactions

Energy Changes, Reaction Rates, and Equilibrium

Gases, Liquids, and Solids

Solutions

Acids and Bases

Nuclear Chemistry

Introduction to Organic Molecules and Functional Groups

Alkanes

Unsaturated Hydrocarbons

Organic Compounds That Contain Oxygen, Halogen, or Sulfur

The Three-Dimensional Shape of Molecules

Aldehydes and Ketones

Carboxylic Acids, Esters, and Amides

Amines and Neurotransmitters

Lipids

Carbohydrates

Nucleic Acids and Protein Synthesis

Digestion and the Conversion of Food Into Energy

Carbohydrate, Lipid, and Protein Metabolism

Filters

D-Amino acids have the -NH₃⁺ group on the left side in the Fischer projection.

Since amino acids contain a base (NH₂ group)and an acid (COOH), proton transfer from the acid to the base forms a salt called a/an _____, which contains both a positive and a negative charge.