Question 1

At which pH does a protein have a net negative charge?

Accepted Answer

A)  at its isoelectric point 
B)  never 
C)  at the pH above its isoelectric point 
D)  at the pH below its isoelectric point 
A)  at its isoelectric point 
B)  never 
C)  at the pH above its isoelectric point 
D)  at the pH below its isoelectric point

Question 2

Which of the following is an allosteric protein?

Accepted Answer

A)  hemoglobin 
B)  myoglobin 
C)  both hemoglobin and myoglobin 
D)  neither hemoglobin nor myoglobin 
A)  hemoglobin 
B)  myoglobin 
C)  both hemoglobin and myoglobin 
D)  neither hemoglobin nor myoglobin

Question 3

Which of the following statements is true of the isoelectric point of amino acids?

Accepted Answer

A)  It is the same for all amino acids. 
B)  It is the pH at which an amino acid conducts electricity. 
C)  It is the pH at which an amino acid has equal numbers of positive and negative charges. 
D)  All of these statements are true. 
A)  It is the same for all amino acids. 
B)  It is the pH at which an amino acid conducts electricity. 
C)  It is the pH at which an amino acid has equal numbers of positive and negative charges. 
D)  All of these statements are true.

Question 4

Which of the following amino acids has a hydroxyl side chain?

Accepted Answer

A)  asparagine 
B)  glutamine 
C)  threonine 
D)  none of these 
A)  asparagine 
B)  glutamine 
C)  threonine 
D)  none of these

Question 5

Which of the following explains the unusually high melting points of amino acids?

Accepted Answer

A)  their unusually high molecular weights 
B)  the polarity of their side chains 
C)  the presence of nitrogen atoms in their side chains 
D)  their existence as zwitterions in polar solvents 
A)  their unusually high molecular weights 
B)  the polarity of their side chains 
C)  the presence of nitrogen atoms in their side chains 
D)  their existence as zwitterions in polar solvents

Question 6

Which of the following is a β-hydroxy-α-amino acid?

Accepted Answer

A)  asparagine 
B)  serine 
C)  tryptophan 
D)  none of these 
A)  asparagine 
B)  serine 
C)  tryptophan 
D)  none of these

Question 7

Which of the following amino acid side chains is hydrophilic?

Accepted Answer

A)  acidic 
B)  basic 
C)  polar but neutral 
D)  all of these 
A)  acidic 
B)  basic 
C)  polar but neutral 
D)  all of these

Question 8

Which of the following denaturing agents affects disulfide bonds?

Accepted Answer

A)  detergent 
B)  heat 
C)  heavy metals 
D)  urea 
A)  detergent 
B)  heat 
C)  heavy metals 
D)  urea

Question 9

Neurotransmitters known as catecholamines are formed from which amino acid?

Accepted Answer

A)  cysteine 
B)  threonine 
C)  tyrosine 
D)  valine 
A)  cysteine 
B)  threonine 
C)  tyrosine 
D)  valine

Question 10

Which of the following pair of amino acids has nonpolar side chains?

Accepted Answer

A)  cysteine and glycine 
B)  cysteine and methionine 
C)  histidine and methionine 
D)  phenylalanine and tryptophan 
A)  cysteine and glycine 
B)  cysteine and methionine 
C)  histidine and methionine 
D)  phenylalanine and tryptophan

Question 11

Which of the following amino acids contains iodine atoms in its structure?

Accepted Answer

A)  leucine 
B)  lysine 
C)  thyroxine 
D)  tyrosine 
A)  leucine 
B)  lysine 
C)  thyroxine 
D)  tyrosine

Question 12

Which of the following amino acids are linked via metal ions?

Accepted Answer

A)  arginine and glutamic acid 
B)  glutamic acid and aspartic acid 
C)  isoleucine and lysine 
D)  phenylalanine and alanine 
A)  arginine and glutamic acid 
B)  glutamic acid and aspartic acid 
C)  isoleucine and lysine 
D)  phenylalanine and alanine

Question 13

Which of the following denaturing agents opens up the hydrophobic regions of a protein?

Accepted Answer

A)  detergents 
B)  heat 
C)  heavy metals 
D)  urea 
A)  detergents 
B)  heat 
C)  heavy metals 
D)  urea

Question 14

Hydroxyurea is used to treat and control the symptoms of _____.

Accepted Answer

A)  malaria 
B)  diabetes 
C)  sickle cell anemia 
D)  phenylketonuria 
A)  malaria 
B)  diabetes 
C)  sickle cell anemia 
D)  phenylketonuria

Question 15

Which of the following pair of amino acids has polar but neutral side chains?

Accepted Answer

A)  cysteine and methionine 
B)  cysteine and serine 
C)  histidine and methionine 
D)  phenylalanine and tryptophan 
A)  cysteine and methionine 
B)  cysteine and serine 
C)  histidine and methionine 
D)  phenylalanine and tryptophan

Question 16

What is the chemical name of serotonin?

Accepted Answer

A)  5-hydroxyphenylalanine 
B)  5-hydroxytryptamine 
C)  3-hydroxytyrosine 
D)  3-hydroxyvaline 
A)  5-hydroxyphenylalanine 
B)  5-hydroxytryptamine 
C)  3-hydroxytyrosine 
D)  3-hydroxyvaline

Question 17

Which of the following amino acids has a guanidino group in its side chain?

Accepted Answer

A)  asparagine 
B)  glutamic acid 
C)  arginine 
D)  none of these 
A)  asparagine 
B)  glutamic acid 
C)  arginine 
D)  none of these

Question 18

Identify the correct representation of the given tripeptide.

Accepted Answer

A)  Ala-Cys-Asp 
B)  Ala-Cys-Glu 
C)  Asp-Cys-Ala 
D)  Glu-Cys-Ala 
A)  Ala-Cys-Asp 
B)  Ala-Cys-Glu 
C)  Asp-Cys-Ala 
D)  Glu-Cys-Ala

Question 19

Which of the following amino acids has an imidazole group side chain?

Accepted Answer

A)  lysine 
B)  tryptophan 
C)  histidine 
D)  tyrosine 
A)  lysine 
B)  tryptophan 
C)  histidine 
D)  tyrosine

Question 20

How are amino acids primarily linked in a protein?

Accepted Answer

A)  by peptide bonds 
B)  by hydrogen bonds 
C)  by ester bonds 
D)  by ionic bonds 
A)  by peptide bonds 
B)  by hydrogen bonds 
C)  by ester bonds 
D)  by ionic bonds

Exam 21: Proteins

At which pH does a protein have a net negative charge?

Which of the following is an allosteric protein?

Which of the following statements is true of the isoelectric point of amino acids?

Which of the following amino acids has a hydroxyl side chain?

Which of the following explains the unusually high melting points of amino acids?

Which of the following is a β-hydroxy-α-amino acid?

Which of the following amino acid side chains is hydrophilic?

Which of the following denaturing agents affects disulfide bonds?

Neurotransmitters known as catecholamines are formed from which amino acid?

Which of the following pair of amino acids has nonpolar side chains?

Which of the following amino acids contains iodine atoms in its structure?

Which of the following amino acids are linked via metal ions?

Which of the following denaturing agents opens up the hydrophobic regions of a protein?

Hydroxyurea is used to treat and control the symptoms of _____.

Which of the following pair of amino acids has polar but neutral side chains?

What is the chemical name of serotonin?

Which of the following amino acids has a guanidino group in its side chain?

Identify the correct representation of the given tripeptide.

Which of the following amino acids has an imidazole group side chain?

How are amino acids primarily linked in a protein?

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