CHEM 2770 Midterm: CHEM 2770 277Dec-2000 Exam
31 Jan 2019
School
Department
Course
Professor
THE UNIVERSITY OF MANITOBA
DATE: Dec. 19, 2000 Final EXAMINATION
PAPER NO.: 554/555 PAGE NO.: 1 of 12
DEPARTMENT & COURSE NO.: 2.277/60.277 Time: 2 HOURS
EXAMINATION: Elements of Biochemistry I EXAMINER: Drs. D.Burton and A. Scoot
GENERAL INSTRUCTIONS
1. You must mark the answer sheet with pencil (not pen).
2. Put your name and enter your student number on the answer sheet.
3. The examination consists of multiple choice questions. Choose what you think is the best,
correct answer and record your choice on the answer sheet. There is only ONE CORRECT
answer.
4. This exam will count for 60% of your final mark.
2. Hydrophobic interactions:
A) primarily involve the effect of polar solutes on the entropy of aqueous systems.
B) do not contribute to the structure of water-soluble proteins.
C) refer to the ability of water to denature proteins.
D) are the driving force in the formation of micelles of amphipathic compounds in water
2. The pH of a sample of blood is 7.4. The pH of a sample of gastric juice is 1.4. The blood sample has:
A) 5.29 times lower [H ] than the gastric juice.
+
B) 6 times lower [H ] than the gastric juice.
+
C) 6,000 times lower [H ] than the gastric juice
+
continued on next page...
C) 6,000 times lower [H ] than the gastric juice.
D) a million times lower [H ] than the gastric juice.
+
E) 0.189 times the [H ] as the gastric juice.
+
a
3. Phosphoric acid is tribasic, with pK values of 2.14, 6.86 and 12.4. The ionic form that predominates
at pH 3.2 is:
34
A) H PO
24
B) H PO
6
4
C) HPO 26
4
D) PO 36
a
4. A compound has a pK of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30
mL of 1.0 M hydrochloric acid. The resulting solution is pH:
A) 7.58
B) 7.4
C) 7.22
D) 6.8
E) 6.53
a
5. One hundred mL of 0.1 M NaOH is added to 55 mL of 0.2 M lactic acid. (The pK of lactic acid is 4.1).
The resulting mixture has a pH close to:
A) 2
B) 3
C) 4
D) 5
THE UNIVERSITY OF MANITOBA
DATE: Dec. 19, 2000 Final EXAMINATION
PAPER NO.: 554/555 PAGE NO.: 2 of 12
DEPARTMENT & COURSE NO.: 2.277/60.277 Time: 2 HOURS
EXAMINATION: Elements of Biochemistry I EXAMINER: Drs. D.Burton and A. Scoot
E) 6
6. In a highly acidic solution, pH = 1, the dominant form of glycine is:
2 2
A) NH - CH - COOH
32
B) NH - CH - COOH
+
2 2
C) NH - CH - COO
&
32
D) NH - CH - COO
+ &
2 3
E) NH - CH - COO
+ &
7. In an "-helix, the R groups on the amino acid residues:
A) are found on the outside of the helix spiral.
B) generate the hydrogen bonds that form the helix.
C) stack within the interior of the helix.
D) cause only right-handed helices to form.
E) alternate between the outside and the inside of the helix.
8. Which of the following statements about proteins is true?
A) Proteins are generally very loosely structured.
B) In water-soluble proteins, hydrophobic (nonpolar) amino acid residues are generally buried and
Document Summary
You must mark the answer sheet with pencil (not pen). Put your name and enter your student number on the answer sheet. Choose what you think is the best, correct answer and record your choice on the answer sheet. This exam will count for 60% of your final mark. The ph of a sample of blood is 7. 4. The ph of a sample of gastric juice is 1. 4. 5. 29 times lower [h ] than the gastric juice. 6 times lower [h ] than the gastric juice. 6,000 times lower [h ] than the gastric juice. 6,000 times lower [h ] than the gastric juice. a million times lower [h ] than the gastric juice. 0. 189 times the [h ] as the gastric juice. Phosphoric acid is tribasic, with pk values of 2. 14, 6. 86 and 12. 4. The ionic form that predominates at ph 3. 2 is: a.
