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BS 161 FINAL EXAM 2025 UPDATED ACTUAL
EXAM WITH CORRECT SOLUTIONS.
In yeast signal transduction, the yeast cells
A)secrete molecules that result in response by other yeast
cells.
B)must physically and directly interact.
C)produce signal molecules that change themselves so they
can interact with one another.
D)produce response molecules that diffuse to other yeast cells.
E)mate, after which the new cells secrete hybrid signals. -
correct answer- A
Which of the following is true for the signaling system in an
animal cell that lacks the ability to
produce GTP?
A)It would employ a transduction pathway directly from an
external messenger.
B)It could activate only the epinephrine system.
C)It would not be able to activate and inactivate the G protein
on the cytoplasmic side of the
plasma membrane.
D)It would use ATP instead of GTP to activate and inactivate
the G protein on the
cytoplasmic side of the plasma membrane.
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E)It would be able to carry out reception and transduction but
would not be able to respond
to a signal. - correct answer- C
Because most receptors are membrane proteins, which of the
following is usually true?
A)They open and close in response to protein signals.
B)They change their conformation after binding with signal
polypeptides.
C)They are only attached to one membrane surface: exterior or
interior.
D)They preferentially bind with lipid or glycolipid signal
molecules.
E)They lead to changes in intracellular ion concentration. -
correct answer- B
Since steroid receptors are located intracellularly, which of the
following is true?
A)The receptor molecules are themselves lipids or glycolipids.
B)The steroid/receptor complex can cross the nuclear
membrane.
C)The receptor molecules are free to move in and out of most
organelles.
D)The unbound steroid receptors are quickly recycled by
lysosomes.
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E)The concentration of steroid receptors must be relatively high
in most cells. - correct answer- B
The receptors for a group of signaling molecules known as
growth factors are often
A)cyclic AMP.
B)ligand-gated ion channels.
C)neurotransmitters.
D)receptor tyrosine kinases.
E)G protein-coupled receptors. - correct answer- D
Binding of a signaling molecule to which type of receptor leads
directly to a change in the
distribution of ions on opposite sides of the membrane?
A)phosphorylated receptor tyrosine kinase dimer
B)ligand-gated ion channel
C)G protein-coupled receptor
D)intracellular receptor
E)receptor tyrosine kinase - correct answer- B
If an adult person has a faulty version of the human analog to
ced-4 of the nematode, which of
the following is most likely to result?
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A)activation of a developmental pathway found in the worm but
not in humans
B)webbing of fingers or toes
C)a form of cancer in which there is insufficient apoptosis
D)neurodegeneration
E)excess skin exfoliation - correct answer- C
A drug designed to inhibit the response of cells to testosterone
would almost certainly result in
which of the following?
A)an increase in cytosolic calcium concentration
B)an increase in receptor tyrosine kinase activity
C)lower cytoplasmic levels of cAMP
D)a decrease in G protein activity
E)a decrease in transcriptional activity of certain genes - correct
answer- E
Which of the following is a correct association?
A)GTPase activity and hydrolysis of GTP to GDP
B)adenylyl cyclase activity and the conversion of cAMP to AMP
C)phosphorylase activity and the catabolism of glucose
D)phosphodiesterase activity and the removal of phosphate
groups
BS 161 FINAL EXAM 2025 UPDATED ACTUAL
EXAM WITH CORRECT SOLUTIONS.
In yeast signal transduction, the yeast cells
A)secrete molecules that result in response by other yeast
cells.
B)must physically and directly interact.
C)produce signal molecules that change themselves so they
can interact with one another.
D)produce response molecules that diffuse to other yeast cells.
E)mate, after which the new cells secrete hybrid signals. -
correct answer- A
Which of the following is true for the signaling system in an
animal cell that lacks the ability to
produce GTP?
A)It would employ a transduction pathway directly from an
external messenger.
B)It could activate only the epinephrine system.
C)It would not be able to activate and inactivate the G protein
on the cytoplasmic side of the
plasma membrane.
D)It would use ATP instead of GTP to activate and inactivate
the G protein on the
cytoplasmic side of the plasma membrane.
,2 | Page
E)It would be able to carry out reception and transduction but
would not be able to respond
to a signal. - correct answer- C
Because most receptors are membrane proteins, which of the
following is usually true?
A)They open and close in response to protein signals.
B)They change their conformation after binding with signal
polypeptides.
C)They are only attached to one membrane surface: exterior or
interior.
D)They preferentially bind with lipid or glycolipid signal
molecules.
E)They lead to changes in intracellular ion concentration. -
correct answer- B
Since steroid receptors are located intracellularly, which of the
following is true?
A)The receptor molecules are themselves lipids or glycolipids.
B)The steroid/receptor complex can cross the nuclear
membrane.
C)The receptor molecules are free to move in and out of most
organelles.
D)The unbound steroid receptors are quickly recycled by
lysosomes.
,3 | Page
E)The concentration of steroid receptors must be relatively high
in most cells. - correct answer- B
The receptors for a group of signaling molecules known as
growth factors are often
A)cyclic AMP.
B)ligand-gated ion channels.
C)neurotransmitters.
D)receptor tyrosine kinases.
E)G protein-coupled receptors. - correct answer- D
Binding of a signaling molecule to which type of receptor leads
directly to a change in the
distribution of ions on opposite sides of the membrane?
A)phosphorylated receptor tyrosine kinase dimer
B)ligand-gated ion channel
C)G protein-coupled receptor
D)intracellular receptor
E)receptor tyrosine kinase - correct answer- B
If an adult person has a faulty version of the human analog to
ced-4 of the nematode, which of
the following is most likely to result?
, 4 | Page
A)activation of a developmental pathway found in the worm but
not in humans
B)webbing of fingers or toes
C)a form of cancer in which there is insufficient apoptosis
D)neurodegeneration
E)excess skin exfoliation - correct answer- C
A drug designed to inhibit the response of cells to testosterone
would almost certainly result in
which of the following?
A)an increase in cytosolic calcium concentration
B)an increase in receptor tyrosine kinase activity
C)lower cytoplasmic levels of cAMP
D)a decrease in G protein activity
E)a decrease in transcriptional activity of certain genes - correct
answer- E
Which of the following is a correct association?
A)GTPase activity and hydrolysis of GTP to GDP
B)adenylyl cyclase activity and the conversion of cAMP to AMP
C)phosphorylase activity and the catabolism of glucose
D)phosphodiesterase activity and the removal of phosphate
groups
