Feb 7th, 2013
Time: 1 hr and 15 min
This test has multiple choice: 24 Marks.
Fill in the blanks: 10 Marks
Peptide structure: 6 Marks
There are a total of 10 pages of this exam.
You are allowed to use a non-programmable calculator. For multiple choice: Choose the BEST answer and indicate your choice on the scantron. Please use a pencil. 1
1. Which of the following weak interactions is NOT due to differences in electrical charge distribution?
hydrophobic interactions. hydrogen bonds. dipole-diople interactions. ionic interactions.
London dispersion forces.
2. Which of the following amino acids could form a hydrogen-bonding interaction between their R groups?
a) Glutamine and Alanine
b) Glutamine and Valine
c) Glutamine and Phenylalanine
d) Glutamine and Isoleucine
e) Glutamine and Tryptophan
3. There are several amino acid side chains that are always charged at physiological pH. These are:
Gln, Asn, Lys, and Arg.
Glu, Asp, Lys, and Arg.
Lys, His, and Arg.
Glu, Asp, Lys, Arg, and His.
4. After synthesis, a globular protein spontaneously folds because:
a) water interacts with polar residues on the protein surface.
b) nonpolar residues coalesce through the hydrophobic effect.
c) disulphide bridges form.
d) thermal energy randomly achieves the most stable conformation.
e) polar residues form hydrogen bonds within the protein.
5. If an aqueous solution has a hydrogen ion concentration of 10 -5 M what is the concentration of the hydroxyl ion?
a) 10-5 M
b) 10-7 M
c) 10-9 M
d) 10-11 M
e) 10-13 M
6. An acid, HA, has a concentration of 0.075 M and its conjugate base, A- ,has a concentration of 0.025M at pH 6. What is the pKa of HA?
7. A BIO 2020 student does a Western blot, shown below. Unfortunately the
Western blot reveals 5 different bands, due to the