Question 1

Which of the following amino acids absorbs UV radiation at 280 nm?

Accepted Answer

A)  phenylalanine 
B)  tryptophan 
C)  tyrosine 
D)  all of these 
A)  phenylalanine 
B)  tryptophan 
C)  tyrosine 
D)  all of these D

Question 2

How many naturally occurring amino acids are commonly found in proteins?

Accepted Answer

A)  10 
B)  20 
C)  25 
D)  100 
A)  10 
B)  20 
C)  25 
D)  100 B

Question 3

Which of the following is true of the atoms in a protein's backbone unit?

Accepted Answer

A)  All of them are in a straight line. 
B)  All of them are in the same plane. 
C)  All of them have tetrahedral geometry. 
D)  None of these are correct. 
A)  All of them are in a straight line. 
B)  All of them are in the same plane. 
C)  All of them have tetrahedral geometry. 
D)  None of these are correct. B

Question 4

What is the conformation of the peptide bond that is present between the amino acids in a protein?

Accepted Answer

A)  planar 
B)  chair 
C)  bent 
D)  nonplanar 
A)  planar 
B)  chair 
C)  bent 
D)  nonplanar

Question 5

What is the most important aspect of an amino acid's side chain?

Accepted Answer

A)  its polarity 
B)  its shape 
C)  its size 
D)  none of these 
A)  its polarity 
B)  its shape 
C)  its size 
D)  none of these

Question 6

Which of the following pair of amino acids has sulfur-containing 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 7

Which of the following amino acids is not optically active?

Accepted Answer

A)  alanine 
B)  glycine 
C)  tryptophan 
D)  none, all of these are optically active 
A)  alanine 
B)  glycine 
C)  tryptophan 
D)  none, all of these are optically active

Question 8

Which of the following defines the primary structure of a protein?

Accepted Answer

A)  the geometric arrangement of the backbone atoms of a protein 
B)  the geometric arrangement of the side chains of a protein 
C)  the sequence of the amino acids in a protein 
D)  all of the above 
A)  the geometric arrangement of the backbone atoms of a protein 
B)  the geometric arrangement of the side chains of a protein 
C)  the sequence of the amino acids in a protein 
D)  all of the above

Question 9

Which of the following proteins is a hormone?

Accepted Answer

A)  casein 
B)  hemoglobin 
C)  insulin 
D)  all of these 
A)  casein 
B)  hemoglobin 
C)  insulin 
D)  all of these

Question 10

How many different tripeptides can be made from glycine and valine?

Accepted Answer

A)  4 
B)  6 
C)  8 
D)  12 
A)  4 
B)  6 
C)  8 
D)  12

Question 11

Which of the following regions of proteins are affected by the denaturing agent urea?

Accepted Answer

A)  hydrogen bonds 
B)  disulfide bonds 
C)  hydrophobic regions 
D)  salt bridges 
A)  hydrogen bonds 
B)  disulfide bonds 
C)  hydrophobic regions 
D)  salt bridges

Question 12

Which of the following is true of the relationship between the primary structure and the function of a protein?

Accepted Answer

A)  A change in one amino acid always affects the function of a protein. 
B)  A change in one amino acid may or may not affect the function of a protein. 
C)  A change in one amino acid never affects the function of a protein. 
D)  The primary structure of a protein and its function are not related. 
A)  A change in one amino acid always affects the function of a protein. 
B)  A change in one amino acid may or may not affect the function of a protein. 
C)  A change in one amino acid never affects the function of a protein. 
D)  The primary structure of a protein and its function are not related.

Question 13

Which of the following statements is true of the water solubility of proteins?

Accepted Answer

A)  Both fibrous and globular proteins are insoluble in water. 
B)  Both fibrous and globular proteins are soluble in water. 
C)  Fibrous proteins are insoluble in water. 
D)  Globular proteins are insoluble in water. 
A)  Both fibrous and globular proteins are insoluble in water. 
B)  Both fibrous and globular proteins are soluble in water. 
C)  Fibrous proteins are insoluble in water. 
D)  Globular proteins are insoluble in water.

Question 14

Which pair of the amino acids is the precursors of norepinephrine and epinephrine?

Accepted Answer

A)  aspartic acid and glutamic acid 
B)  cysteine and methionine 
C)  isoleucine and leucine 
D)  phenylalanine and tyrosine 
A)  aspartic acid and glutamic acid 
B)  cysteine and methionine 
C)  isoleucine and leucine 
D)  phenylalanine and tyrosine

Question 15

Which of the following proteins is associated with the movement of muscles?

Accepted Answer

A)  actin 
B)  ferritin 
C)  hemoglobin 
D)  insulin 
A)  actin 
B)  ferritin 
C)  hemoglobin 
D)  insulin

Question 16

Which of the following amino acids functions as a hormone?

Accepted Answer

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

Question 17

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 18

Which of the following statements is true of zwitterions?

Accepted Answer

A)  They are positively charged. 
B)  They are negatively charged. 
C)  They are electrically neutral. 
D)  They are made up of basic amino acids. 
A)  They are positively charged. 
B)  They are negatively charged. 
C)  They are electrically neutral. 
D)  They are made up of basic amino acids.

Question 19

Which of the following dipeptides is glycylalanine?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 20

Which of the following amino acids can be easily dimerized?

Accepted Answer

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

Exam 21: Proteins

Which of the following amino acids absorbs UV radiation at 280 nm?

How many naturally occurring amino acids are commonly found in proteins?

Which of the following is true of the atoms in a protein's backbone unit?

What is the conformation of the peptide bond that is present between the amino acids in a protein?

What is the most important aspect of an amino acid's side chain?

Which of the following pair of amino acids has sulfur-containing side chains?

Which of the following amino acids is not optically active?

Which of the following defines the primary structure of a protein?

Which of the following proteins is a hormone?

How many different tripeptides can be made from glycine and valine?

Which of the following regions of proteins are affected by the denaturing agent urea?

Which of the following is true of the relationship between the primary structure and the function of a protein?

Which of the following statements is true of the water solubility of proteins?

Which pair of the amino acids is the precursors of norepinephrine and epinephrine?

Which of the following proteins is associated with the movement of muscles?

Which of the following amino acids functions as a hormone?

Identify the correct representation of the given tripeptide.

Which of the following statements is true of zwitterions?

Which of the following dipeptides is glycylalanine?

Which of the following amino acids can be easily dimerized?

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