QUIZ 3, BICH 410 (MWF 1:50 PM), Wednesday, Nov. 2, 1994
Clearly circle the letter corresponding to your answer for each problem. There are seven problems. Six count 3 points each, and one is worth 2 points. No partial credit given for multiple-choice questions.
1. A typical protein will not be denatured by:
- A. urea
- B. pH 10
- C. sodium dodecyl sulfate
- D. 2,3-bisphosphoglycerate
- E. heating to 90 degrees C
2. Carbon monoxide:
- A. binds to myoglobin but not hemoglobin
- B. binds to sickle cell hemoglobin better than to normal hemoglobin
- C. "locks" hemoglobin in the T state
- D. binds tighter to the heme group than oxygen
- E. converts the protoporphyrin heme group to bilirubin
3. Which of the following bond-pairs within a peptide backbone show free rotation around both bonds?
- A. Ca-C and N-Ca
- B. C=O and N-Ca
- C. N-C and Ca-C
- D. C=O and N-C
- E. N-Ca and N-C
4. Which of the following is least important to describe cooperative binding of oxygen to hemoglobin?
- A. A sigmoid binding curve of the ligand.
- B. The Hill coefficient equals 3.
- C. The presence of a heme group.
- D. The T to R transition
- E. The presence of multiple subunits
5. A sequence of amino acids in a protein is found to be -threonine-glycine-proline-glycine-. This sequence is most probably part of a(n):
- A. antiparallel ß sheet
- B. alpha-helix
- C. ß turn
- D. parallel ß sheet
- E. alpha-keratin
6. An a-helix would be destabilized most by:
- A. interactions between neighboring aspartate and arginine residues
- B. the presence of an arginine residue near the carboxyl terminus of the alpha-helix
- C. interactions between two adjacent valine residues
- D. binding to a specific sequence on double-stranded DNA
- E. the presence of two lysine residues near the amino terminus of the alpha-helix
7. (2 points) In an alpha-helix, the R groups on the amino acid residues:
- A. are found on the outside of the helix spiral.
- B. cause only right-handed helices to form.
- C. alternate between the outside and the inside of the helix.
- D. contain the atoms involved in hydrogen bonds that directly stabilize the helix.
- E. stack within the interior of the helix.