Quiz 3, BICH 410 (MWF3-3:50), Friday, Oct. 16, 1998

Clearly circle the letter corresponding to your answer for each problem. There are six problems, four of which count 3 points, and two for 4 points. No partial credit given for multiple-choice questions.
gas constant R 8.315 J/mole-K; Faraday constant F 96.5 kJ/mole-volt

1) A sphingolipid that contains a single monosaccharide residue as part of its polar head group is known as a:
Answer: B


2. Which of the following would you expect to be least soluble in water?
Answer: D


3) Which of the following statements is true about the passive transport of water across membranes?
Answer: C


4) Which of the following statements is not true about glycosaminoglycans?
Answer: E


5) (4 pts) Which of the following structures shows the linkage found in an N-linked glycoprotein?

Answer: C; asparagine side-chain N-C bond to C-1 of N-acetyl-glucosamine


6) (4 pts) What is the free energy change for the transport of calcium ions (Ca+2) across a membrane from a region (left) where the concentration is 100 micromolar to a region (right) where the concentration is 1 micromolar. A membrane potential of 50 mV exists across the membrane where the left side is more negative than the right side. The temperature is 37 C.
Answer: B; deltaG = RT ln([Ca+2]right/[Ca+2]left) + ZF(membrane potential)
deltaG = (8.315 J/mole-K)(310 K) / (1000 J/kJ) ln (1/100) + (2)(96.5 kJ/mole-volt)(.05 volt)
deltaG = -2.2 kJ/mole