Transcript Document

The distribution of scores is shown below. Please note that the number below each bin is the
maximum of that bin, so for example the bin labeled ’60’ includes scores from >50 to =60. The
mean for the test was 60.4. Midterm grades will be submitted according to the following
breakdown: A: ≥71; B:61-70; C:50-60; D:40-50; F:<40. Final grades will include + and – values.
If your score is below 50, please understand that I am available to help you improve it on
subsequent tests.
Frequency
20
18
16
14
12
Frequency
10
8
6
4
2
0
20
30
40
50
60
70
80
90
More
For the multiple-choice questions, the correct answer is indicated by the grader.
For the answers that required a narrative response, see the following remarks:
Question 1: The two basic mechanisms I presented to you were gene duplication
followed by separate evolution, and alternative splicing. Some students suggested
various types of post-translational modification such as differential glycosylation, and
this is an unexpected but valid answer for which I added credit in several cases.
Question 2: The fish uses medial, oxidative slow muscle for swimming in the river and
adds fast glycolytic muscle when climbing a fish ladder or spawning. The lateral
muscle contains most of the stored glycogen and thus is responsible for the burst of
glycogen utilization during high exertion.
Question 3: Soluble proteins are disposed of by polyubiquitination by ubiquitin ligase
followed by proteolysis by protosomes. The end-products are free amino acids,
which can be used to generate new proteins.
Question 4: The two factors are: “substrate availability” and “ADP availability”. Some
students mentioned individual substrates such as glucose or pyruvate. I decided not
to give credit for answers that were specific since the number of different substrates
that can feed intermediary oxidative metabolism is so large.