From the perspective of the cell receiving the message, the three stages of cell signaling are
A) the paracrine, local, and synaptic stages.
B) signal reception, signal transduction, and cellular response.
C) signal reception, nucleus disintegration, and

B) signal reception, signal transduction, and cellular response.

The process of transduction usually begins
A) when the chemical signal is released from the alpha cell.
B) when the signal molecule changes the receptor protein in some way.
C) after the target cell divides.
D) after the third stage of cell signaling is c

B) when the signal molecule changes the receptor protein in some way.

Synaptic signaling between adjacent neurons is like hormone signaling in which of the following ways?
A) It sends its signal molecules through the blood.
B) It sends its signal molecules quite a distance.
C) It requires calcium ions.
D) It requires bindin

D) It requires binding of a signaling molecule to a receptor.

Which of the following is (are) true of ligand-gated ion channels?
A) They are important in the nervous system.
B) They lead to changes in sodium and calcium concentrations in cells.
C) They open or close in response to a chemical signal.
D) Only A and B

E) A, B, and C are true.

What would be true for the signaling system in an animal cell that lacks the ability to produce GTP?
A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
B) It could activate only the epinephrine

A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.

Up to 60% of all medicines used today exert their effects by influencing what structures in the cell membrane?
A) tyrosine-kinases receptors
B) ligand-gated ion channel receptors
C) growth factors
D) G proteins
E) cholesterol

D) G proteins

Which of the following are chemical messengers that pass through the plasma membrane of cells and have receptor molecules in the cytoplasm?
A) insulin
B) testosterone
C) cAMP
D) epinephrine

C) cAMP

Which is true of transcription factors?
A) They regulate the synthesis of DNA in response to a signal.
B) Some transcribe ATP into cAMP.
C) They initiate the epinephrine response in animal cells.
D) They control which genes are expressed.
E) They are need

D) They control which genes are expressed.

Chemical signal pathways
A) operate in animals, but not in plants.
B) are absent in bacteria, but are plentiful in yeast.
C) involve the release of hormones into the blood.
D) often involve the binding of signal molecules to a protein on the surface of a

D) often involve the binding of signal molecules to a protein on the surface of a target
cell.

The receptors for a group of signaling molecules known as growth factors are often
A) ligand-gated ion channels.
B) G-protein-linked receptors.
C) cyclic AMP.
D) receptor tyrosine kinases.
E) neurotransmitters.

D) receptor tyrosine kinases.

The general name for an enzyme that transfers phosphate groups from ATP to a protein is
A) phosphorylase.
B) phosphatase.
C) protein kinase.
D) ATPase.
E) protease.

C) protein kinase.

Adenylyl cyclase has the opposite effect of which of the following?
A) protein kinase
B) protein phosphatase
C) phosphodiesterase
D) phosphorylase
E) GTPase

C) phosphodiesterase

Binding of a signaling molecule to which type of receptor leads directly to a change in distribution of ions on opposite sides of the membrane?
A) receptor tyrosine kinase
B) G protein-coupled receptor
C) phosphorylated receptor tyrosine kinase dimer
D) l

D) ligand-gated ion channel

The activation of receptor tyrosine kinases is characterized by
A) dimerization and phosphorylation.
B) IP3 binding.
C) a phosphorylation cascade.
D) GTP hydrolysis.
E) channel protein shape change.

A) dimerization and phosphorylation.

Consider this pathway: epinephrine ? G protein-coupled receptor ? G protein ? adenylyl cyclase ? cAMP. Identify the second messenger.
A) cAMP
B) G protein
C) GTP
D) adenylyl cyclase
E) G protein-coupled receptor

A) cAMP