Chapter 09 – Cell Communication
Clarify Question
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What is the key concept addressed by the question?
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What type of thinking is required?
Gather Content
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What do you know about an inhibitor of the estrogen receptor? What other information
is related to the question?
Choose Answer
•
Given what you now know, what information is most likely to produce the correct
answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 09 – Cell Communication
22. Tamoxifen is a drug that is used to treat breast cancer. It inhibits the activities of
the estrogen receptor in breast epithelial cells, which are the cells that are relevant to breast
cancer. One of the concerns that scientists had during the development of Tamoxifen as a
therapy for breast cancer was that other cell types require estrogen signaling for their function.
For example, it is known that cells in bone tissue require estrogen signaling. As a result, there
was a concern that use of Tamoxifen would lead to bone loss in patients. In reality, however,
researchers were surprised to find that Tamoxifen actually led to an increase in bone density
in breast cancer patients. At the same time, Tamoxifen did inhibit the activity of the estrogen
receptor in breast epithelial cells in these patients. What is the best explanation for this
finding?
Chapter 09 – Cell Communication
Clarify Question
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What is the key concept addressed by the question?
estrogen receptor.
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What type of thinking is required?
Gather Content
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What do you know about the effects of tamoxifen on different cells after binding to the
estrogen receptor? What other information is related to the question?
Choose Answer
•
Given what you now know, what information is most likely to produce the correct
answer?
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 09 – Cell Communication
23. A mutation in the DNA-binding domain of a steroid hormone receptor is most likely to
affect what aspect of receptor function?
Chapter 09 – Cell Communication
Clarify Question
•
What is the key concept addressed by the question?
•
What type of thinking is required?
Gather Content
•
What do you know about steroid receptors? What other information is related to the
question?
Choose Answer
•
Given what you now know, what information is most likely to produce the correct
answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
Chapter 09 – Cell Communication
24. You are having lunch with an elderly friend when suddenly he begins to experience chest
pain and tightness. He reaches into his pocket, gets out one of his nitroglycerin tablets and
quickly takes it. After the episode passes, your friend asks you how the nitroglycerin helps his
angina. You explain that nitroglycerin gets converted by cells to nitric oxide (NO) causing the
smooth muscle cells of the blood vessel to relax and increase blood flow to the heart. He
pushes you for a more detailed explanation, so you explain further that:
25. What is the mechanism by which binding of testosterone to the testosterone receptor
leads to upregulated gene transcription?
Chapter 09 – Cell Communication
26. How are receptor tyrosine kinases and steroid hormone receptors similar?
27. Some cancers are caused by the overexpression of receptor tyrosine kinases (RTKs). It is
known that RTK signaling pathways commonly stimulate cell division. Why would the
overexpression of receptor tyrosine kinases lead to cancer development?
Chapter 09 – Cell Communication
Clarify Question
•
What is the key concept addressed by the question?
•
What type of thinking is required?
Gather Content
•
What do you know about receptor tyrosine kinases? What other information is related to
the question?
Choose Answer
•
Given what you now know, what information is most likely to produce the correct
answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
28. What signaling pathway commonly makes use of a G protein to transduce the signal?
29. Your research project involves the characterization of a particular signal transduction
pathway. Specifically, you have been studying a receptor tyrosine kinase and protein X,
which initiates downstream events. You are certain that protein X is part of the signal
transduction pathway, but have been unable to identify a direct protein-protein interaction
between the receptor tyrosine kinase and the protein X. What should you do next in your
attempt to identify a link between the receptor tyrosine kinase and protein X?
Chapter 09 – Cell Communication
Clarify Question
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What is the key concept addressed by the question?
•
What type of thinking is required?
Gather Content
•
What do you know about the signaling pathway activated by a receptor tyrosine kinase?
What other information is related to the question?
Choose Answer
•
Given what you now know, what information is most likely to produce the correct
answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 09 – Cell Communication
30. The protein SOS is a guanine nucleotide exchange factor for Ras. SOS helps facilitate the
exchange of GDP for GTP. What would be the effect of a mutation that inhibits the
interaction between SOS and Ras?
Clarify Question
•
What is the key concept addressed by the question?
•
What type of thinking is required?
Gather Content
•
What do you know about the interaction between Ras and SOS? What other information
is related to the question?
Choose Answer
•
Given what you now know, what information is most likely to produce the correct
answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 09 – Cell Communication
31. Many receptor tyrosine kinase (RTK) pathways lead to the activation of Ras. To activate
Ras, it is necessary to recruit a guanine nucleotide exchange factor to the plasma membrane,
because Ras is a membrane associated protein. Guanine nucleotide exchange factors, such as
SOS, stimulate the exchange of GDP for GTP. However, SOS cannot bind directly to most
RTKs. The protein Grb2 has a domain that can bind to phosphorylated tyrosines, and another
domain that can bind to SOS. Therefore, Grb2 can bind to active RTKs and recruit SOS to the
plasma membrane. Grb2 is an example of what kind of signaling molecule?
32. Ste5 binds to MAPKKK, MAPKK, and MAPK to organize the kinase cascade. What type
of signaling molecule is Ste5?
Chapter 09 – Cell Communication
33. Many receptor tyrosine kinase pathways have MAPK as a downstream signaling
component. MAPK can phosphorylate target proteins. What type of signaling molecule is
MAPK?
34.
A small number of cell surface receptors can ultimately generate a large intracellular response due to activation of kinase
cascades. This is referred to as:
35. What enzyme phosphorylates MAP kinase kinase?
Chapter 09 – Cell Communication
36. The cell surface receptors that can act only indirectly on plasma membrane-bound
enzymes or ion channels are called:
37. G protein-coupled receptors are the largest family of cell surface receptors. Each receptor
passes through the plasma membrane how many times?
38. In the nitric oxide signaling pathway, nitric oxide activates an enzyme that can convert
many molecules of GTP into molecules of cGMP. cGMP is a small molecule that can diffuse
through the cytoplasm and bind to an enzyme called protein kinase G (PKG). Binding of
cGMP to PKG leads to a change in the confirmation of PKG that leads to its activation. What
type of signaling molecule is cGMP?
Chapter 09 – Cell Communication
39. Some enzymatic receptors and most G protein-coupled receptors transmit the signal into
the cytoplasm by utilizing other substances within the cytoplasm that are referred to as:
40. A mutation that affects Ca++ binding to calmodulin is most likely to interfere with what
aspect of a signal transduction pathway?
41. If the effector protein phospholipase C failed to cleave phosphatidylinositol-4,5-
bisphosphate (PIP2), the action of what enzyme would be affected?
Chapter 09 – Cell Communication
Clarify Question
•
What is the key concept addressed by the question?
•
What type of thinking is required?
Gather Content
•
What do you know about enzymes activated by inositol triphosphate? What other
information is related to the question?
Choose Answer
•
Given what you now know, what information is most likely to produce the correct
answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 09 – Cell Communication
42. What is similar about G protein-coupled receptors (GPCRs) and receptor tyrosine kinases
(RTKs)?
43. The function of adenylyl cyclase is to:
44. What is the difference between Ras and the G proteins bound to G protein coupled
receptors (GPCRs)?
Chapter 09 – Cell Communication
45. What second messenger is directly involved in activating protein kinase C (PKC)?