D103 Final Exam Questions with Correct Answers
Which of the following list the order of events occurring during a signaling event ?
A. Stimulus, transduction, receptor, effector, response.
B. Stimulus, receptor, transduction, effector, response.
C. Stimulus, receptor, effector, transduction, response.
D. Stimulus, response, transduction, effector.
Which of the following is not a commonly used mechanism to regulate activity of
proteins in a signaling pathway ?
A. Phosphorylation.
B. Unmasking of a nuclear localization signal (NLS).
C. Proteolytic degradation.
D. Protein synthesis.
E. All of the above are examples of commonly used mechanisms to regulate proteins in a
signaling pathway.
Which of the following properties would be found in a ligand that does not require a
transmembrane receptor ?
A. It is hydrophilic.
B. It can bind directly to DNA.
C. It is always present at a higher concentration outside the cell relative to the
cytoplasm.
D. It is hydrophobic.
E. It is a zwitterion.
Which of the following signals doesn't need a plasma membrane receptor to enter a cell
?
,A. Insulin - a hormone.
B. Adenosine - a purine nucleoside.
C. HIV - a virus.
D. Estrogen - a steroid hormone
E. Ferrous iron - Fe2+.
Which of the following features would be unlikely to be found in an effective signaling
molecule ?
A. Ability to be synthesized rapidly.
B. Ability to be degraded rapidly.
C. Ability to be stored, released and recovered.
D. Ability to bind to all transmembrane receptors.
E. Ability to be transported from the site of synthesis to a site of action.
Which best explains why different types of cells might respond to the same extra-
cellular signaling molecule in a different manner ?
A. Because cells can vary in the length of their cell cycle.
B. Because different types of cells can have different signaling machinery components.
C. Because the core-signaling pathway is similar in all cell types.
D. Because different cell types bind extra-cellular signaling molecules in the different
manner.
E. Because the genome sequence can vary between cells.
Why would nitric oxide be a poor endocrine signaling molecule ?
A. Because it is only synthesized by a few cell types.
B. Because it would be taken up by all cell types due to the fact that it does not need a
cell surface receptor.
,C. Because it has a very short lifetime. D. Because it would only be synthesized in cells
containing arginine.
Which of the following describes a correct order of events that occurs during signaling
between to induce vasodilation ?
A. Endothelial cell secretes acetylcholine -> G-protein coupled receptor in smooth
muscle cell binds to guanylyl cyclase -> [increased cGMP] induces protein kinase G
activity that leads to smooth muscle relaxation.
B. Acetylcholine bind to G-protein coupled receptor on surface of smooth muscle cell ->
smooth muscle cell synthesizes nitric oxide (NO) -> NO diffuses into endothelial cell ->
activates guanylyl cyclase -> [increased cGMP] leads to smooth muscle relaxation.
C. Activation of Ca2+- calmodulin in endothelial cell -> smooth muscle cell synthesizes
nitric oxide (NO) -> NO activates guanylyl cyclase -> [increased cGMP] leads to smooth
muscle relaxation.
D. Activation of nitric oxide synthase in endothelial cell -> NO activates guanylyl cyclase
in smooth muscle cell -> [increased cGMP] leads to smooth muscle relaxation.
Which of the following changes in enzyme activity could produce the strongest effect on
vasodilation ?
A. Increase guanylyl cyclase and decrease cGMP phosphodiesterase.
B. Increase both guanylyl cyclase and cGMP phosphodiesterase.
C. Decrease guanylyl cyclase and increase cGMP phosphodiesterase.
D. Decrease both guanylyl cyclase and cGMP phosphodiesterase.
Which of the following is a feature of the androgen receptor (AR) ?
A. The AR can bind to testosterone and transport it across the plasma membrane.
B. The AR acts as a transcriptional repressor in the absence of testosterone.
, C. The AR's subcellular location can be controlled by masking and unmasking of amino
acid motifs.
D. Binding of testosterone to the AR induces it to bind Hsp90.E. Mutation of the AR's
activation domain prevents it from binding to DNA.
Which domain in a steroid hormone receptor is not required for it to become active in
the nucleus ?
A. The DNA binding domain.
B. The transcriptional co-activator domain.
C. The ligand binding domain.
D. All of the above domains are required for a steroid hormone receptor to be active.
Which of the following statements about the estrogen receptor (ER) and the retinoic
acid receptor (RAR) is true ?
A. The ER has a nuclear localization signal (nls) while the RAR does not.
B. The ER and RAR can each act as a transcriptional repressor while located in the
nucleus.
C. The ER and RAR can bind the same ligands.
D. The RAR can signal while located at the inner leaflet of the plasma membrane.E.
The RAR and the ER each have a DNA binding domain.
Which of the following is NOT a common mechanism used to regulate activity
ofsignaling proteins ?
A. Binding of another molecule to the signaling protein.
B. Masking of a NLS signal in the signaling protein by another protein.
C. Degradation of the signaling molecule by proteolysis.
D. Uptake of the signaling protein by the ER.
Which of the following list the order of events occurring during a signaling event ?
A. Stimulus, transduction, receptor, effector, response.
B. Stimulus, receptor, transduction, effector, response.
C. Stimulus, receptor, effector, transduction, response.
D. Stimulus, response, transduction, effector.
Which of the following is not a commonly used mechanism to regulate activity of
proteins in a signaling pathway ?
A. Phosphorylation.
B. Unmasking of a nuclear localization signal (NLS).
C. Proteolytic degradation.
D. Protein synthesis.
E. All of the above are examples of commonly used mechanisms to regulate proteins in a
signaling pathway.
Which of the following properties would be found in a ligand that does not require a
transmembrane receptor ?
A. It is hydrophilic.
B. It can bind directly to DNA.
C. It is always present at a higher concentration outside the cell relative to the
cytoplasm.
D. It is hydrophobic.
E. It is a zwitterion.
Which of the following signals doesn't need a plasma membrane receptor to enter a cell
?
,A. Insulin - a hormone.
B. Adenosine - a purine nucleoside.
C. HIV - a virus.
D. Estrogen - a steroid hormone
E. Ferrous iron - Fe2+.
Which of the following features would be unlikely to be found in an effective signaling
molecule ?
A. Ability to be synthesized rapidly.
B. Ability to be degraded rapidly.
C. Ability to be stored, released and recovered.
D. Ability to bind to all transmembrane receptors.
E. Ability to be transported from the site of synthesis to a site of action.
Which best explains why different types of cells might respond to the same extra-
cellular signaling molecule in a different manner ?
A. Because cells can vary in the length of their cell cycle.
B. Because different types of cells can have different signaling machinery components.
C. Because the core-signaling pathway is similar in all cell types.
D. Because different cell types bind extra-cellular signaling molecules in the different
manner.
E. Because the genome sequence can vary between cells.
Why would nitric oxide be a poor endocrine signaling molecule ?
A. Because it is only synthesized by a few cell types.
B. Because it would be taken up by all cell types due to the fact that it does not need a
cell surface receptor.
,C. Because it has a very short lifetime. D. Because it would only be synthesized in cells
containing arginine.
Which of the following describes a correct order of events that occurs during signaling
between to induce vasodilation ?
A. Endothelial cell secretes acetylcholine -> G-protein coupled receptor in smooth
muscle cell binds to guanylyl cyclase -> [increased cGMP] induces protein kinase G
activity that leads to smooth muscle relaxation.
B. Acetylcholine bind to G-protein coupled receptor on surface of smooth muscle cell ->
smooth muscle cell synthesizes nitric oxide (NO) -> NO diffuses into endothelial cell ->
activates guanylyl cyclase -> [increased cGMP] leads to smooth muscle relaxation.
C. Activation of Ca2+- calmodulin in endothelial cell -> smooth muscle cell synthesizes
nitric oxide (NO) -> NO activates guanylyl cyclase -> [increased cGMP] leads to smooth
muscle relaxation.
D. Activation of nitric oxide synthase in endothelial cell -> NO activates guanylyl cyclase
in smooth muscle cell -> [increased cGMP] leads to smooth muscle relaxation.
Which of the following changes in enzyme activity could produce the strongest effect on
vasodilation ?
A. Increase guanylyl cyclase and decrease cGMP phosphodiesterase.
B. Increase both guanylyl cyclase and cGMP phosphodiesterase.
C. Decrease guanylyl cyclase and increase cGMP phosphodiesterase.
D. Decrease both guanylyl cyclase and cGMP phosphodiesterase.
Which of the following is a feature of the androgen receptor (AR) ?
A. The AR can bind to testosterone and transport it across the plasma membrane.
B. The AR acts as a transcriptional repressor in the absence of testosterone.
, C. The AR's subcellular location can be controlled by masking and unmasking of amino
acid motifs.
D. Binding of testosterone to the AR induces it to bind Hsp90.E. Mutation of the AR's
activation domain prevents it from binding to DNA.
Which domain in a steroid hormone receptor is not required for it to become active in
the nucleus ?
A. The DNA binding domain.
B. The transcriptional co-activator domain.
C. The ligand binding domain.
D. All of the above domains are required for a steroid hormone receptor to be active.
Which of the following statements about the estrogen receptor (ER) and the retinoic
acid receptor (RAR) is true ?
A. The ER has a nuclear localization signal (nls) while the RAR does not.
B. The ER and RAR can each act as a transcriptional repressor while located in the
nucleus.
C. The ER and RAR can bind the same ligands.
D. The RAR can signal while located at the inner leaflet of the plasma membrane.E.
The RAR and the ER each have a DNA binding domain.
Which of the following is NOT a common mechanism used to regulate activity
ofsignaling proteins ?
A. Binding of another molecule to the signaling protein.
B. Masking of a NLS signal in the signaling protein by another protein.
C. Degradation of the signaling molecule by proteolysis.
D. Uptake of the signaling protein by the ER.
