BISC305: Final ACTUAL UPDATED
QUESTIONS AND CORRECT ANSWERS
Which type of intercellular signaling involves production of a signal molecule that interacts
only with receptors on cells next to the cell producing the signal?
A. autocrine
B. paracrine
C. endocrine
D. exocrine - CORRECT ANSWERS✅✅B. paracrine
Which subunit(s) of the heterotrimeric G protein is (are) in the lipid bilayer?
A. alpha subunit only
B. alpha and beta subunits
C. beta and gamma subunits
D. alpha and gamma subunits - CORRECT ANSWERS✅✅D. alpha and gamma subunits
Which subunit of the G protein binds to the G protein coupled Receptor (GPCR) once a
ligand binds to the GPCR?
A. alpha subunit
B. beta subunit
C. gamma subunit - CORRECT ANSWERS✅✅A. alpha subunit
With intercellular signaling involving GPCRs, the molecule that directly prouces the "second
messenger" is referred to as what?
A. receptor
B. ligand
C. effector
D. G protein - CORRECT ANSWERS✅✅C. effector
What is responsible for desensitization of the GPCR?
A. internalization and degradation of the receptor only
,B. blockage of G protein binding by arrestin only
C. both of the above - CORRECT ANSWERS✅✅C. both of the above
Most mutations in GPCRs that cause disease have constitutive activation (continuous
signaling)
A. True B. False - CORRECT ANSWERS✅✅A. true
The protein domain that is found in > 150 different proteins that allows them to bind to
phosphoinositides (lipid second messengers), thus recruiting them to the membrane to
participate in signal transduction is which of the following?
A. PK domain
B. PH domain
C. SH2 domain
D. SH3 domain - CORRECT ANSWERS✅✅B PH domain
After phospholipase C (PLC) splits PIP2 into IP3 and diacylglycerol (DAG), what does
soluble IP3 do?
A. binds to IP3 receptor in ER membrane to release Ca2+
B. activates protein kinase C, which phosphorylates a variety of targets - CORRECT
ANSWERS✅✅A. binds IP3 receptor in ER membrane to release Ca2+
The 2nd messenger cAMP is generated by which enzyme in response to an activated GPCR?
A. adenosine triphosphatase
B. Phospholipase C
C. protein kinase C
D. adenylyl cyclase - CORRECT ANSWERS✅✅D. adenylyl cyclase
Most effects of cAMP occur through activation of
A. Ca2+
B. protein kinase A (PKA)
C. protein kinase C (PKC)
D. phospholipase C (PLC) - CORRECT ANSWERS✅✅B. protein kinase A (PKA)
, Receptor protein tyrosine kinases (RTKs) are involved in signaling that mostly controls
metabolism
A. true B. false - CORRECT ANSWERS✅✅B. false
Most RTKs are activated by
A. receptor glycosylation
B. PLC
C. heterotrimeric G proteins
D. receptor dimerization - CORRECT ANSWERS✅✅D. receptor dimerization
Two different domains found in various signaling proteins that bind to phosphotyrosine
residues are
A. SH2 and SH3
B. SH3 and PTB
C. SH2 and PTB
D. SH3 and Ca-binding - CORRECT ANSWERS✅✅C. SH2 and PTB
The purpose of a docking protein, like IRS, is what?
A. to increase the available phosphotyrosines for signaling proteins to bind
B. to decrease the available phosphotyrosines for signaling proteins to bind - CORRECT
ANSWERS✅✅A. to increase the available phosphotyrosines for signaling proteins to bind
The adaptor protein Grb2 conatins
A. 1 SH2 and 1 SH3 domain
B. 2 SH2 and 1 SH3 domain
C. 1 SH2 and 2 SH3 domains
D. 2 SH2 and 2 SH3 domains - CORRECT ANSWERS✅✅C. 1 SH2 and 2 SH3 domains
(look at figure on exam 3)
The small G protein ras becomes active when
QUESTIONS AND CORRECT ANSWERS
Which type of intercellular signaling involves production of a signal molecule that interacts
only with receptors on cells next to the cell producing the signal?
A. autocrine
B. paracrine
C. endocrine
D. exocrine - CORRECT ANSWERS✅✅B. paracrine
Which subunit(s) of the heterotrimeric G protein is (are) in the lipid bilayer?
A. alpha subunit only
B. alpha and beta subunits
C. beta and gamma subunits
D. alpha and gamma subunits - CORRECT ANSWERS✅✅D. alpha and gamma subunits
Which subunit of the G protein binds to the G protein coupled Receptor (GPCR) once a
ligand binds to the GPCR?
A. alpha subunit
B. beta subunit
C. gamma subunit - CORRECT ANSWERS✅✅A. alpha subunit
With intercellular signaling involving GPCRs, the molecule that directly prouces the "second
messenger" is referred to as what?
A. receptor
B. ligand
C. effector
D. G protein - CORRECT ANSWERS✅✅C. effector
What is responsible for desensitization of the GPCR?
A. internalization and degradation of the receptor only
,B. blockage of G protein binding by arrestin only
C. both of the above - CORRECT ANSWERS✅✅C. both of the above
Most mutations in GPCRs that cause disease have constitutive activation (continuous
signaling)
A. True B. False - CORRECT ANSWERS✅✅A. true
The protein domain that is found in > 150 different proteins that allows them to bind to
phosphoinositides (lipid second messengers), thus recruiting them to the membrane to
participate in signal transduction is which of the following?
A. PK domain
B. PH domain
C. SH2 domain
D. SH3 domain - CORRECT ANSWERS✅✅B PH domain
After phospholipase C (PLC) splits PIP2 into IP3 and diacylglycerol (DAG), what does
soluble IP3 do?
A. binds to IP3 receptor in ER membrane to release Ca2+
B. activates protein kinase C, which phosphorylates a variety of targets - CORRECT
ANSWERS✅✅A. binds IP3 receptor in ER membrane to release Ca2+
The 2nd messenger cAMP is generated by which enzyme in response to an activated GPCR?
A. adenosine triphosphatase
B. Phospholipase C
C. protein kinase C
D. adenylyl cyclase - CORRECT ANSWERS✅✅D. adenylyl cyclase
Most effects of cAMP occur through activation of
A. Ca2+
B. protein kinase A (PKA)
C. protein kinase C (PKC)
D. phospholipase C (PLC) - CORRECT ANSWERS✅✅B. protein kinase A (PKA)
, Receptor protein tyrosine kinases (RTKs) are involved in signaling that mostly controls
metabolism
A. true B. false - CORRECT ANSWERS✅✅B. false
Most RTKs are activated by
A. receptor glycosylation
B. PLC
C. heterotrimeric G proteins
D. receptor dimerization - CORRECT ANSWERS✅✅D. receptor dimerization
Two different domains found in various signaling proteins that bind to phosphotyrosine
residues are
A. SH2 and SH3
B. SH3 and PTB
C. SH2 and PTB
D. SH3 and Ca-binding - CORRECT ANSWERS✅✅C. SH2 and PTB
The purpose of a docking protein, like IRS, is what?
A. to increase the available phosphotyrosines for signaling proteins to bind
B. to decrease the available phosphotyrosines for signaling proteins to bind - CORRECT
ANSWERS✅✅A. to increase the available phosphotyrosines for signaling proteins to bind
The adaptor protein Grb2 conatins
A. 1 SH2 and 1 SH3 domain
B. 2 SH2 and 1 SH3 domain
C. 1 SH2 and 2 SH3 domains
D. 2 SH2 and 2 SH3 domains - CORRECT ANSWERS✅✅C. 1 SH2 and 2 SH3 domains
(look at figure on exam 3)
The small G protein ras becomes active when
