Quiz 3, BICH 410 (TuTh 12:45-2), Tuesday, Nov. 5, 1996
Clearly circle the letter corresponding to your answer for each problem. There are seven problems, six of which count 3 points, and one is worth 2 points. No partial credit given for multiple-choice questions.
1. The structure of ATP
- A. contains a beta-N-glycosidic linkage.
- B. contains a pyranose ring.
- C. preferentially adopts a chair conformation.
- D. is uncharged at neutral pH.
- E. contains a ketose sugar.
2. Which of the following properties is NOT common to D-glucose and D-ribose?
- A. They are reducing sugars.
- B. They exist preferentially in a cyclic structure.
- C. They form intramolecular hemiacetal bonds.
- D. They are hexoses.
- E. They have functional groups that can form glycosidic linkages.
3. Which of the following statements about glycosaminoglycans is true?
- A. They constitute 5 percent of the weight of proteoglycans.
- B. They contain positively charged substituent groups.
- C. They are attached to proteins by O-glycosidic linkages at glutamic acid residues.
- D. They are heteropolysaccharides.
- E. They are a major component of the cell wall of bacteria.
4. If one carries out the partial mild acid hydrolysis of glycogen or starch and then isolates from the product all the trisaccharides present, how many different kinds of trisaccharides are possible? Disregard alpha or beta anomers.
Answer: D; trisaccharide means two glycosidic linkages and the possible linkages are 1-4 or 1-6; hence, possible structures are i) both 1-4 linkages; ii) one 1-4 and one 1-6 linkage on "left" monosaccharide; iii) one 1-4 and one 1-6 linkage on "right" monosaccharide; iv) both 1-6 linkages
- A. one
- B. two
- C. three
- D. four
- E. five
5. The structures of thymine and uracil differ because:
- A. only one contains a keto group at position 4.
- B. only one contains a methyl group at position 5.
- C. one is a pyrimidine and the other is a purine.
- D. only one contains an amino group at position 5.
- E. only one contains an amino group at position 4.
6. From the abbreviated name of the compound Gal(ß1->4)Glc, we know that: (Gal = galactose; Glc = glucose)
- A. the compound is dextrorotatory.
- B. the glucose is in its pyranose form.
- C. the galactose residue is at the reducing end.
- D. the glucose residue is the beta anomer.
- E. C-4 of glucose is joined to C-1 of galactose by a glycosidic bond.
7. (2 pts) If a region of one strand of a DNA double helix has the sequence 5'-ACCTGGAATTC-3', what is the sequence of the complementary region of the other strand?
- A. 5'-TGGACCTTAAG-3'
- B. 5'-CTTAAGGTCCA-3'
- C. 5'-GAATTCCAGGT-3'
- D. 5'-ACCTGGAATTC-3'
- E. 5'-UGGACCUUAAG-3'