Chem 361
Quiz1 (each question is worth 5 points)
Name:
Date: Sep 29, 2011
1. Which of the following is considered as a noncovalent bond?
A)
B)
C)
electrostatic interactions
hydrogen bonds
van der Waals interactions
D)
E)
All of the above.
None of the above.
2. What pairs of atoms in bases are involved in hydrogen bonds?
A)
B)
C)
N—H and O—H
N—H and S—H
O—H and P—O
D)
E)
All of the above.
None of the above.
3. What two properties of water are important for biological interactions?
A)
B)
C)
the polarity of water
the density of water
the cohesive properties of water
D)
E)
a and c
b and c
4. List atoms commonly found in biological molecules that are often hydrogen-bond
acceptors.
A) carbon
B) oxygen
C) nitrogen
D) b and c
E) All of the above.
5. What happens to nonpolar molecules in water?
A)
B)
C)
They dissolve independently.
They aggregate together.
They precipitate.
D)
E)
All of the above.
None of the above.
6. What is the [A-]/[HA] ratio when the weak acid is in a solution one pH unit above its
pKa?
A)
B)
C)
1:1
1 : 10
10 : 1
D)
E)
2:1
None of the above.
2
7. Stereochemistry can be easily depicted in a simple form using
A)
B)
C)
Ball-and-stick models.
ribbon diagrams.
Space-filling models.
D)
E)
Fisher projections.
None of the above.
8. Which of the following is the Henderson-Hasselbach equation?
A)
B)
C)
 A-  
pH = pKa  log    
  HA  


 A  
pH = pKa     
  HA  


  HA  
pH = pKa  log  - 
 A  
 
D)
  A-  
pKa = pH  log    
  HA 


E)
None of the above.
D)
E)
None of the above.
All of the above.
9. What determines a protein’s function?
A)
B)
C)
structure
gene sequence
N-terminal amino acids
10. Key properties of proteins include
A)
B)
C)
D)
E)
a wide range of functional groups.
an ability to possess either rigid or flexible structures as dictated by functional
requirements.
the ability to interact with other proteins.
a and b.
All of the above.
3
11. At a pH of 1, what charged group(s) are present in glycine?
A) -NH3+
B) -COO-
C) -NH2+
D) a and b
E) a, b, and c
12. Which amino acids contain reactive aliphatic hydroxyl groups?
A)
B)
C)
serine and methionine
serine and threonine
methionine and threonine
D)
E)
cysteine and methionine
cysteine and threonine
13. Name three amino acids that are positively charged at a neutral pH.
A)
B)
C)
lys, arg, and his
his, arg, and cys
cys, arg, and met
D)
E)
lys, arg, and pro
arg, glu, and his
14. In the following peptide, which amino acid is the N-terminus?
Phe-Ala-Gly-Arg
A) Ala
B) Phe
C) Phe and Arg
D) Arg
E) None of the above.
15. Which of the following affect the sedimentation of a particle?
A)
B)
C)
mass
shape
the density of the solution
D)
E)
16. Cyanogen bromide cleaves the peptide bond at
A)
B)
C)
D)
E)
the carboxyl side of Arg and Lys residues.
the carboxyl side of Met residues.
the amino terminus.
None of the above.
All of the above.
All of the above.
a and b
4
17. Trypsin cleaves the peptide bond at
A)
B)
C)
D)
E)
the carboxyl side of Arg and Lys residues.
the carboxyl side of Met residues.
the amino terminus.
None of the above.
All of the above.
18. Which of the following techniques can be used to determine the site of a disulfide
bond?
A)
B)
C)
Edman degradation
affinity chromatography
diagonal electrophoresis
Answer Key:
1. D
2. A
3. D
4. D
5. B
6. C
7. D
8. A
9. A
10. D
11. A
12. B
13. A
14. B
15. D
16. B
17. A
18. C
D)
E)
MALDI-TOF
SDS-PAGE