課程名稱︰細胞生物學
課程性質︰必修
課程教師︰沈湯龍
開課學院：植微系
開課系所︰生農院
考試日期（年月日）︰2018/06/28 14:20-16:20
考試時限（分鐘）：120分鐘
試題 :
01. Actin filiments are a major element of the cytoskeleton. The cytoskeleton
provides a framework for the cell and acts as a scaffold that both
determines cell shape and positions organelles within cells. For example,
the cytoskeleton provides the tracks along which organelles move. At the
same time, the cytoskeleton is subject to cleavage by proteins like
ADF/cofilin. What is the apparent function of ADF/cofilin?
02. How does Ca2+ molecularly regulate the activity of myosin motors?
03. According to the generally accepted fluid mosaic model of membrane
structure, membranes are two-dimensional fluids through which proteins can
move freely in lateral directions. Provide an example of a membrane protein
that is not free to move laterally within a plasma membrane.
04. How does the plasma membrane come to be hyperpolarized locally during
action potential reversal?
05. How is proline hydroxylation in collagen encoded in the genome? What is the
relationship between this encoding mechanism and scurvy?
06. Unlike polysaccharides such as glycogen or cellulose,
glycosaminoglycans(GAGs) are highly negaively charged. What is the sourse
and function of this negative charge?
07. Growth factors and cytokines both lead to tyrosine phosphorylation through
receptors, but they do so through different mechanisms. What is the key
difference between the receptors for these two classes of ligands in terms
of their tyrosine kinase activity?
08. As a cell biologist for a pharmaceutical company, you are charged with
developing a drug to inhibit the cAMP-cAMP response element binding protein
(CREB) pathway. Briefly describe the cascade leading to CREB activation and
where one might target a drug to block its activation.
09. What are three cellular processes in which the Ras/Raf/MAP kinase pathway
is activated?
10. During G2 the Wee1 protein phosphorylates tyrosine-15 of the Cdc2 protein
kinase, thus inactivating it. Only once dephosphorylation occurs and Cdc2
becomes active can the cell pass from G2 into M and proceed to cell
division. Can you think of a reason why the Weelprotein was named as such?
11. Why is Rb, a product of the retinoblastoma gene, now termed a member of a
family of proteins designated tumor suppressor genes?
12. One of the hallmark characteristics of apoptosis is fragmentation of
nuclear DNA. Which protein is responsible for this fragmentation, and what
is the mechanism by which it degrades the DNA?
13. Bcl-2 is an antiapoptotic protein which, under normal conditions,
contributes to the balance of acivity of numerous proapoptotic and
antiapoptotic proteins. What would be the result of a gain-of-function
mutation in the bcl-2 gene that led to constant and significant elevation
in cellular Bcl-2 protein levels?
14. Signaling pathways mediate many cellular processes, as explained in
Chapter 15. Apoptosis is also regulated by multiple signaling pathways.
Breifly describe two signaling pathways that regulate apoptosis.
15. Cellular transformation from normal to tumor cells is a hallmark of cancer.
The focus assay represents the first and most widely used assay to assess
cell transformation. Describe the focus assay.
16. How does adenoviral E1A:Rb lead to excessive cell proliferation following
viral infection?
17. Describe how the first oncogene was discovered.
18. Please list 2 examples of stem cells in maintaining the homeostasis of the
corresponding physiology.