X402, course grade and final exam answer sheet. Spring 2006.
Total test points:
Exam score is on the exam. 20 = A, 15 = B, 10 = C, 5 = D. (ignoring +/-)
In figuring your course grade, I look at several things. First, I average your four test letter
grades. For most people, this will give a proper course grade. But I do look to see if one of
your early tests was unusually low (and I may consider that, discounting the early low score a
little). After that, I generally look over the whole picture, trying to make sure everything looks
fair and consistent.
For test point total, the nominal cutoffs (ignoring +/-) are: A = 69, B = 52, C = 34, D = 17
(possible = 87). Your test total is shown above; check for accuracy of my records.
If there are any questions that might reasonably affect your course grade, please contact me
ASAP. I’ll mail in the official grades Tuesday morning 5/30. (Of course, legitimate problems
can be fixed later, but it is easier before submission.) Beyond that, feel free to call/e-mail
anytime to discuss other issues, or to chat. If you want to do further work from Ouellette, I am
happy to discuss it with you, or to read any written work.
Additional feedback/suggestions always welcomed; e-mail is fine. Comments/suggestions on
the web pages are particularly welcomed. If you haven’t already done so, look at the
Supplemental Information page at the web site for some things you might comment on. (You
can also send me anonymous messages by using the message form at the web site.)
A brief answer key follows. Alternative answers are reasonable in some cases. I have avoided
drawing structures here as much as possible.
1. Charge difference is 2; the avian virus enzyme is -2 relative to the human virus enzyme.
Glu has a negatively charged side chain, whereas lysine has a positively charged side chain.
R M Krug, Virology: Clues to the virulence of H5N1 viruses in humans. Science
311:1562, 3/17/06. News. The feature discussed in the question is just one part of the
story of why the bird and human viruses behave differently. This article discusses this
difference, and others.