Deck 13: Signal Transduction Pathways

Question 1

The cytosolic side, or β subunit, of the insulin receptor is a ________________ kinase.

Answer 1

tyrosine

Question 2

________________ is the membrane protein that catalyzes the conversion of ATP to cAMP.

Answer 2

Adenylate cyclase

Question 3

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
____________: The enzyme that catalyzes the cleavage of PIP2.

Answer 3

h

Question 4

The ________________ receptor undergoes dimerization and cross-phosphorylation when activated.

Question 5

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
____________: The primary messenger responsible for the "fight or flight" response.

Question 6

Protein kinase A phosphorylates serine and ________________ residues.

Question 7

7TM is an abbreviation for ________________ receptors.

Question 8

The binding of IP3 to the IP3 receptor results in the release of ________________ from the endoplasmic reticulum.

Question 9

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
The inactive form of protein kinase A is ____________.

Question 10

________________ binds to β-andrenergic receptors.

Question 11

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
The ____________ enzyme becomes active when bound to Ca2+ and diacylglycerol.

Question 12

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
____________: The ɑ and subunits of heterotrimeric G proteins are anchored to the cell membrane by being covalently linked to these types of molecule.

Question 13

________________ is a secondary messenger and is abbreviated IP3.

Question 14

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
____________: A gene that leads to the transformation of susceptible cell types into cell types with cancer-like characteristics.

Question 15

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
Ras is a member of the ____________ family of proteins.

Question 16

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
The ____________ protein binds to calcium ions and serves as a Ca2+ sensor in eukaryotic cells.

Question 17

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
The ____________ molecule functions as a secondary messenger.

Question 18

When activated, the insulin receptor results in the mobilization of ________________ transporters to the cell surface.

Question 19

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) protein kinase A (PKA)
b) calmodulin
c) fatty acids
d) proto-oncogene
e) R2C2
f) R1C2
g) cAMP
h) phospholipase C
i) protein kinase C (PKC)
j) epinephrine
k) oncogene
l) small G proteins
The enzyme that becomes active when bound to cAMP is ____________.

Question 20

The ________________ is a calcium-binding unit in many proteins and is characterized by a helix-loop-helix structure.

Question 21

How does the binding of a hormone to receptor activate a G-protein?

A) It causes an exchange of GTP for bound GDP.
B) It causes the γ subunit to be released from binding to the β subunit.
C) It causes an exchange of GDP for bound GTP.
D) A and B.
E) None of the above.

Question 22

The enzyme responsible for induction of the phosphoinositide cascade is:

A) phospholipase C.
B) phospholipase A.
C) C-dependent protein (CDP).
D) All of the above.
E) None of the above.

Question 23

Examples of second messengers include:

A) cAMP.
B) calcium ion.
C) diacyl glycerol.
D) A and B.
E) A, B, and C.

Question 24

Most signal molecules:

A) easily diffuse through the membrane and bind to a receptor in the cytoplasm.
B) bind to membrane receptors and transmit information across a membrane without traversing the membrane.
C) carry out functions in the nucleus after binding to a receptor in the cell membrane.
D) A and C.
E) A, B, and C.

Question 25

The mechanism by which insulin-signaling processes might be terminated include:

A) change in temperature.
B) the aggregation of all protein subunits.
C) protein dephosphorylation by phosphatases.
D) All of the above.
E) None of the above.

Question 26

What is a disadvantage of using common molecules for signaling paths?

Question 27

Cross-phosphorylation is possible when two receptor proteins with kinase domains:

A) are cleaved.
B) form dimers.
C) are internalized into organelles.
D) All of the above.
E) None of the above.

Question 28

Which form of the guanyl nucleotide is bound in the unactivated state?

A) GTP
B) GDP
C) GMP
D) dGTP
E) None of the above.

Question 29

What are the two messenger products formed by cleavage of PIP2?

A) diacylglyercol and inositol 1,4,5-triphosphate
B) diacylglyercol and inositol 1,3,5-triphosphate
C) diacylglyercol and inositol 1,3-diphosphate
D) diacylglyercol phosphate and inositol 1,4,5-trisphosphate
E) None of the above.

Question 30

______________ may be effective anticancer drugs.

A) Monoclonal antibodies against offending receptors
B) EGF mimics
C) Protein kinase inhibitors
D) All of the above.
E) Both A and C.

Question 31

Which of the following amino acids can be phosphorylated?

A) tyrosine, serine, threonine
B) tyrosine, serine, tryptophan
C) serine, threonine, asparagine
D) histidine, serine, phenylalanine
E) tyrosine, methionine, tryptophan

Question 32

When insulin binds to its receptor, which of the following occurs?

A) A PIP2-dependent kinase is activated.
B) Calmodulin binds Ca2+.
C) Sos stimulates the exchange of GTP for GDP.
D) All of the above.
E) None of the above.

Question 33

Advantages of second messengers include that:

A) the signal can be amplified by making many second messengers.
B) second messengers can freely diffuse to other sites within the cell.
C) a few common second messengers can be used in multiple signaling pathways.
D) All of the above.
E) None of the above.

Question 34

Example(s) of disease(s) caused by altered G-protein activity include:

A) whooping cough.
B) cholera.
C) diabetes.
D) A and B.
E) B and C.

Question 35

How many 7TM membranes are there? What are some of their functions?

Question 36

What happens when signaling paths are not terminated properly?

Question 37

What are some of the common structural features of the receptors to which signal molecules bind?

Question 38

Why is bound GTP considered a "clock"?

A) It behaves in specific time intervals.
B) GTP is exchanged for GDP after binding to adenylate cyclase.
C) The Gɑ receptors have intrinsic GTPase activity, hydrolyzing GTP to GDP and Pi.
D) All of the above.
E) None of the above.

Question 39

How is calmodulin activated?

A) by binding of both calcium and potassium
B) by binding Ca2+ when the cytosolic concentration is raised
C) by binding to a positively charged helix on another protein
D) All of the above.
E) None of the above.

Question 40

What is the general mechanism for signal transmission by 7TM receptors?

Question 41

What is meant by an EF hand? Draw or describe the structure.

Question 42

What is the difference between heterotrimeric G proteins and small G proteins?

Question 43

What is the difference between a proto-oncogene and an oncogene?

Question 44

Describe the role of phosphoinositol 4,5-bisphosphate (PIP2) in insulin signal transduction.

Question 45

What steps lead from the activation of a cross-phosphorylated receptor tyrosine kinase to an activated small G protein such as Ras?

Question 46

What are receptor tyrosine kinases? Provide an example.

Question 47

How does binding of epinephrine initiate the cAMP production? Discuss briefly in terms of receptor structure and function.

Question 48

Describe how phosphatidylinositol-4,5-diphosphate is converted into two secondary messengers.

Question 49

How is the hormone-bound activated receptor reset after activation?