BIS 104 PQ #24
24. The data presented in Figure 5 suggest that clustering of integrins in the PM of the cell
stimulates VEGF expression. Remember that clustering in this context means that the integrin
proteins must be induced to move laterally in the pla
BIS 104 PQs 5 & 6 ans 2011
5. In Figure 1a the authors show data from a FACS analysis of LNCaP cells transfected with either a gene
coding for functional 3 integrin or a nonfunctional mutant integrin gene (S75
BIS 104 PQ 9 2011
9. Based on the results depicted in Figure 2 a, b, c, & d, S. De et al. conclude that activation of
tumor integrin 53 controls tumor growth in prostate and breast cancer through the regulation
a. Summarize the experiment
BIS 104 PQ 12 Fall 2011
12. Define the following concepts or terms that are important aspects of microscopy.
d. refractive index
f. numerical aperture (NA):
g. empty magnification
BIA 104 PQ 13 Fall 2011
13. The lipid composition of biomembranes has a strong influence on the physical and
physiological properties of membranes such as the plasma membrane of the cell. Among the
membrane lipids, phospholipids play a major role in deter
BIS 104 PQ 14
The data presented in figures #1 and #2 provide evidence that tumor cells that are stably
transfected with activatable (WT) a5b3 integrin genes are capable of generating tumors
when injected subcutaneously into SCID mice, and that these tumo
BIS 104 PQs 10, 11
10. After many fractionation steps you have partially purified an antibody (IgG) from the
whole blood of an immunized rabbit. The fraction you have obtained has a protein
concentration of 5
BIS 104 PQ #15, #16 Fall 2011
15. Summarize the evidence, both observational and experimental, that tends to support the fluid
mosaic model of biomembrane structure/function. Are there any known biomembrane
characteristics that are not compatible with thi
BIS 104 PQ 17 Fall 2011
17. In Figure 3, parts d and e, we see data from LNCaP and MDA cells grown in culture. The
ELISA technique was used to quantify the amount of VEGFA protein secreted by these cells.
a. What is the ELISA technique?
b. What is vitrone
BIS 104 PQ 18 Fall 2011
18. Figure 3f shows data from an experiment in which the conditioned media from cultured
LNCaP cells was assayed for VEGFA protein by the ELISA technique.
(a) What is the integrin 3 antagonist?
(b) This experiment is designed to sa
BIS 104 PQ 20 Fall 2011
20. Two of the ways in which cells transport small molecular weight solutes from one
membrane bound compartment to another are: (a) facilitated diffusion using channel proteins
and, (b) primary active trasnport. Discuss the signifi
BIS 104 PQ 21
21. Based on experimental data presented in Figure 4, S. De, et al. conclude that transmembrane
signaling through activatable 53 integrin can stimulate VEGF production, which, in turn
controls tumor cell growth and migration.
Summarize the e
BIS 104 PQ 22
22. Mff (mitochondrial fusion factor) is a protein synthesized in the cytoplasm of mammalian
cells and post-translationally transported to the outer membrane of mitochondria.
Describe how you would design a pulse-chase experiment to determin
BIS 104 PQ answers (#1 4)
1. State the HYPOTHESIS that is being tested in the PNAS article by S. De, et al.
Expression of the integrin a5b3 by tumor cells regulates tumor cell VEGF expression, thereby
enhancing tumor growth and angiogenesis. (in this case
BIS 104 PQ 8 ans 2011
8. Proof of a scientific hypothesis is convincing only if supported by a diverse series of experimental evidence.
Your assigned reading Rules of Evidence I , describes three types of evidence.:
Experiments that establish (1) plausibi
BIS 104 PQ 25
In Figure 6, data are presented to support the contention that 53 ligand binding
induces phosphorylation of Shc as part of an outside-to-inside signaling pathway.
a. What is it composed of?
b. Where is it located in free-float
BIS 104 PQ 26
26. The data in Figure 6a show results of experiments designed to search for an intracellular
(cytoplasmic) mediator for the outside-to-inside signal pathway involving 53 integrins in
LNCaP cells. These experiments were designed with the pri
BIS 104 PQ 27
27. Describe the EXPERIMENT that provides the data shown in Figure 6b by listing the steps
of the experimental protocol in chronological order. Refer back to Figure 5 if you have forgotten
how 53 clustering can be stimulated.
BIS 104 PQ 28
28. It has been determined that a cargo vesicle can be moved along a MT toward the plus end
at a rate of ~3 micrometers per second (3 um / sec). And, each individual kinesin motor protein
step covers ~8 nanometers (nm).
a. How many steps can
BIS 104 PQ 29
29. In S. De et al., Figure 6 parts a and b show that WT LNCaP cells activated by Vn (i.e.,
integrins get cross-linked and undergo clustering) is sufficient to increase the recruitment of
p66Shc to the cytoplasmic domain of a5b3. Answer the
BIS 104 PQ 30
30. LNCaP cells expressing (a) WT p66Shc and (b) cells expressing dominant-negative (Y313F)
p66Shc were injected into SCID mice. After seven days of growth, tumors were removed,
sectioned, stained with H&E, and examined by bright-field micro
BIS 104 PQ 31
S. De, et al. used the technique of cellular transfection to create a panel of LNCaP cell lines that
expressed various forms of specific gene products. For each of the transfectants listed below,
describe the structural and functional charac
BIS 104 PQ 32
The conclusions that can be derived from all of the experimental data presented in Figures 1 6
in the S. De et al. article can be summed up in four simple statements:
a. The activation state of 35 integrin plays a critical role in tumor grow
OBSERVATION: LNCap cells lacking functional 53 integrins grow
very slowly and are not stimulated to proliferate when exposed to protein
growth factors. In contrast, LNCap cells with functional 53 integrins
proliferate more rapidly when exposed to growth f
BIS 104 FALL 2011 Exam I answer key
a. VEGFR is located in the plasma membranes of endothelial cells and some cancer cell lines.
b. it is a protein
c. its function is to bind VEGF and transmit this signal across the PM to initiate an cytoplasm
BIS 104 PQ 7 ans 2011
7. For each of the items listed below describe i) its composition and location, and ii) its major function(s).
The first one is done for you as an example of an appropriate answer to this type of question.
A) NUCLEAR PORE COMPLEX (NP
BIS 104 PQ 23
23. It has been hypothesized that vesicles with v-SNARES incorporated into their membranes
can fuse with vesicles bearing t-SNARES when mixed together in vitro. In contrast, batches of
vesicles bearing homologous SNARE proteins (i.e., t-SNAR