Problem Set Chapter 15
1. Which of the following is NOT an example of a second messenger molecule in
signal transduction pathways?
a.
b.
c.
d.
cAMP
Growth Factor
Ca2+
lipid cleavage products
2. Acetylcholine is to phopholipase C in a smooth muscle cell as epinephrine is to
_____________ in a liver cell.
a.
b.
c.
d.
protein kinase C
cAMP
adenylyl cyclase
GTP
3. Which mutant form of Ras is likely to cause a cell to become cancerous
(uncontrolled cell division)?
a.
b.
c.
d.
a mutation that prevents it from binding GTP
a mutation that prevents it from interacting with the Sos GEF protein.
a mutation that destroys its GTPase activity
a mutation that prevents it from activating the MAP kinase cascade
4. Epinephrine binds to adrenergic receptors in liver, smooth muscle, and cardiac
muscle. In liver epinephrine induces glycogen breakdown, in smooth muscle it
leads to muscle relaxation, and in cardiac muscle it leads to muscle contraction.
Which of the following does NOT account for different responses to epinephrine
in each of these cell types:
a.
b.
c.
d.
each cell type has a different adrenergic receptor
different heterotrimeric G proteins are activated in each cell type
adenylyl cyclase is activated in some cells and inactivated in others.
an enzyme that is activated in all three cell types is capable of catalyzing
glycogen breakdown, smooth muscle relaxation, and cardiac muscle
contraction.
5. Beta blocker drugs reduce blood pressure by acting as a __________ to
epinephrine induction of the 1 adrenergic receptor of cardiac muscle.
a.
b.
c.
d.
agonist
antagonist
second messenger
more than one of the above
6. Proteins with SH2 domains are to ___________ in Growth Factor signaling
pathways as heterotrimeric G proteins are to G-Protein Couple Receptors in G
protein signaling pathways.
a.
b.
c.
d.
Ras
Receptor Tyrosine Kinases
MAP kinases
G proteins
7. If you break up liver cells and separate the plasma membranes from the cell
cytoplasm and then add epinephrine to the soluble cytoplasmic protein fraction,
which of the following will occur:
a.
b.
c.
d.
cAMP will be produced
epinephrine will bind the G-protein coupled adrenergic receptor
adenylyl cyclase will be activated
nothing
8. Which of the following mutations in a Receptor Tyrosine Kinase of a cell that
binds a specific Growth Factor will cause the cell to divide constitutively:
a.
b.
c.
d.
mutation of its phosphorylatable Tyrosine to Serine
mutation of its phosphorylatable Tyrosine to Glutamic Acid
mutation of its phosphorylatable Tyrosine to Glycine
mutation of its phosphorylatable Tyrosine to Alanine
9. Which of the following mutations in a Receptor Tyrosine Kinase of a cell that
binds a specific growth factor will prevent the cell from dividing in response to
growth factor: (Multiple correct answers)
a.
b.
c.
d.
mutation of its phosphorylatable Tyrosine to Serine
mutation of its phosphorylatable Tyrosine to Glutamic Acid
mutation of its phosphorylatable Tyrosine to Glycine
mutation of its phosphorylatable Tyrosine to Alanine
10. DAG and IP3 are to __________ as cAMP is to epinephrine.
a.
b.
c.
d.
insulin
acetylcholine
growth factors
glucagons
11. Define each of the following terms used to describe players in signal transduction
pathways:
First Messenger (ligand):
Transducer (receptor):
Adapter:
Effector:
Second Messenger:
Target:
12. For each of the following cellular responses, identify the first messenger (ligand),
transducer (receptor), adapter, effector, second messenger (if there is one), ultimate
targets of the signal transduction pathway:
a. EXAMPLE: Epinephrine-stimulated glycogen breakdown in liver
first messenger: epinephrine
transducer (receptor): G protein coupled receptor (GPCR)
adapter: heterotrimeric G protein complex
effector: Adenylyl Cyclase
second messenger: cAMP
target: Glycogen phosphorylase which catalyzes the rate limiting step in
glycogen breakdown
b. Acetylcholine stimulation of stomach smooth muscle contraction
first messenger:
transducer (receptor):
adapter
effector:
second messenger:
target:
c. Growth factor stimulation of cell growth
first messenger:
transducer (receptor):
adapter
effector:
second messenger:
target:
d. Acetylcholine stimulation of vascular smooth muscle relaxation
first messenger:
transducer (receptor):
adapter
effector:
second messenger:
target:
e. Insulin-induced uptake of glucose and glycogen synthesis
first messenger:
transducer (receptor):
adapter
effector:
second messenger:
target:
f. Receptor mediated cell death
first messenger:
transducer (receptor):
adapter
effector:
second messenger:
target:
g. Cellular damage mediated cell death
first messenger:
transducer (receptor):
adapter
effector:
second messenger:
target: