Name: ________________________________ Student ID: ______________________
1) Briefly describe some of the essential functions of biological membranes. (0.5 pts
each, max 3 pts)
2) Draw a diagram of the major components of a typical plasma membrane (“fluid
mosaic” model) and label them. (0.5 pts each, max 3 pts)
1
Name: ________________________________ Student ID: ______________________
3) Draw the chemical structure of dipalmitoyl phosphatidyl serine and label the various
moieties. (0.5 pts each, 3 pts max)
4) Draw a schematic of a detergent micelle with an integral membrane protein. (1 pt)
2
Name: ________________________________ Student ID: ______________________
5) List different types of membranes found in eukaryotic cells. (0.5 pts each, 3 pts max)
6) Describe briefly (diagram with labels) the biogenesis of a eukaryotic membrane
protein. (3 pts)
3
Name: ________________________________ Student ID: ______________________
7) Which of the following chemicals is/are able to cross phospholipid bilayers without
the aid of a carrier/channel/transporter: Na+, ATP, glucose, water, serine, ethanol,
molecular oxygen, chloride, hemoglobin, iron, H+. (2 pts)
8) Why are high-resolution structures of membrane proteins generally more difficult to
obtain than those of soluble proteins? (2 pts)
4
Name: ________________________________ Student ID: ______________________
9) Approximately, what is the percentage of membrane proteins (as compared to the total
number of proteins) in the human genome? What is the approximate total number of
membrane proteins in the human genome? (2 pts)
10) Briefly, describe the role of detergents in membrane protein structural & functional
studies. Why do different membrane proteins require different detergents? (2 pts)
5
Name: ________________________________ Student ID: ______________________
11) Draw a simple, hypothetical hydrophaty plot for a membrane protein with four
transmembrane helices and label both axes. Will the N- and C-termini be on the same or
on opposite sides of the membrane? (2 pts)
12) From the excerpt of a PDB file below, please extract and list below the Y coordinate
[Å] and the B factor [Å2] of the main chain alpha carbon (C) of the residue listed. What
type of amino acid does it belong to? (2 pts)
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
ATOM
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
N
CA
C
O
CB
CG
CD1
CD2
NE1
CE2
CE3
CZ2
CZ3
CH2
TRP
TRP
TRP
TRP
TRP
TRP
TRP
TRP
TRP
TRP
TRP
TRP
TRP
TRP
A
A
A
A
A
A
A
A
A
A
A
A
A
A
189
189
189
189
189
189
189
189
189
189
189
189
189
189
20.285
19.178
19.255
19.023
17.951
16.600
15.829
15.831
14.635
14.608
16.057
13.602
15.057
13.851
45.608
45.718
46.946
46.972
45.788
45.619
44.482
46.541
44.662
45.899
47.832
46.502
48.423
47.768
6
-3.275
-4.239
-5.129
-6.324
-3.345
-3.921
-3.766
-4.685
-4.411
-4.983
-5.170
-5.725
-5.913
-6.186
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
17.35
18.18
17.53
16.16
18.80
22.87
22.97
21.96
22.73
21.72
21.39
23.05
22.35
23.28
N
C
C
O
C
C
C
C
N
C
C
C
C
C
Name: ________________________________ Student ID: ______________________
13) What is meant by the term ‘structure-function studies’? (2 pts)
14) Why are membrane proteins generally more difficult to work with than soluble
proteins? (2 pts)
7
Name: ________________________________ Student ID: ______________________
15) Desribe how aquaporins allow water to traverse their pore, but prevent proton (H+ or
H3O+) and general cation conductance? Draw a proton wire. (3 pts)
16) Extra credit: When we talked about aquaporins, we talked about a subclass
called aquaglyceroporins. Viewed in the context of this course, why do cells require
large amounts of glycerol? (2 pts)
8