Quiz 2, BICH 410 (MWF 3-3:50P), Friday October 8, 1999

Write your name on each page. Clearly circle your response to multiple-choice questions. No partial credit for multiple-choice questions
gas constant R 8.315 J/mol-K

1. (3 pts) Which amino acid sidechain from the choices below would be the worst nucleophile in an enzyme active site?
Answer: B (see Fig. 11-10)

2. (3 pts) Why does fetal hemoglobin bind oxygen with a higher affinity than adult hemoglobin?
Answer: D

3. (3 pts) Which nucleotide base from the choices below cannot exist in keto vs. enol tautomeric forms?
Answer: A; adenine is only base that lacks a keto group

4. (3 pts) Three essential amino acid residues in the active site of chymotrypsin form a catalytic triad. Which of the following is a role for these residues in catalysis?
Answer: D

5) (2 pts) Which of the following compounds is not a nucleotide?
Answer: A

6) (3 pts) Consider the reaction profile (transition state diagram) shown below. Select the answer that correctly identifies the values 1, 2, and 3 depicted on this graph.
(graph is modified from Fig. 11-5 in book)
Answer: E

7) (3 pts) Consider the two oxygen binding curves for hemoglobin labeled A and B. Which statement(s) is/are true?
(graph consists of two sigmoid curves - curve A on left, curve B on right)
Answer: D