Wednesday, October 12, 2011
Reading & problem assignments for this week DIFFER from what is shown in
the LG, but instead are as shown for 10/14 & 10/19: text pp. 343-363 and 371-
389 and text problems Ch.10 #7,16 and Ch.11 #4,15 and LG problems 32-34.
Reminder: no quiz next Wednesday, 10/19.
PyMOL #6, chymotrypsin, will appear on the prelim, but no other PyMOL.
4. Friday 10/14 2:55 - 4PM in Comstock B108: “How to study for this course”.
discussion of material on the 10/20 prelim, but prof will outline how to study
effectively, and answer questions about the exam.
5. Rooms for the 10/20 exam: Last names A - M in Rockefeller Schwartz
Auditorium; N - Z in Rockefeller 203 (“Auditorium B”).
Lecture from Friday 10/7/10
Regulation of enzyme action
Control of enzyme activity.
Example of aspartate carbamoyltransferase =
Control of chymotrypsinogen activation to chymotrypsin
Intro to biomembranes
unsaturated hydrocarbon chains
, those with at least one double bond, are
very important for
keeping the bilayer somewhat fluid
This is because
saturated, unbranched hydrocarbon chains can pack together tightly, forming a
This tight packing would not allow movement of proteins within the
Unsaturated lipids increase the fluidity of the membrane.
For almost all cases, it is not known why some lipid acyl chains are multiply
In addition, it is not known why there are different chain lengths.
In the middle of page 152 is stearate, abbreviated as 18:0, an example of a
saturated lipid chain.
The structure is straight, as opposed to that of oleate,
abbreviated 18:1, which has one double bond that forms a kink in the molecule.
Now imagine how well many stearate molecules could pack closely together, as
opposed to how poorly oleate molecules would pack with each other and with
other stearate molecules.
(Note: learn the “
system” for describing the
location of double bonds, text pp 343-344).
Nearly a third to half of all the lipid in mammalian plasma membranes is
We do know that
cholesterol decreases the permeability