Physiology Exam 2 Ch. 6 Test Bank
Questions and Answers
usually called
A) responders.
B) receivers.
C) targets.
D) contacts.
E) junctions - Answer-C) targets.
Which is NOT a basic method of cell-to-cell communication?
A) cytoplasmic transfer of signals
B) contact-dependent signals
C) diffused chemical signals
D) nerve and blood-transported signals
E) mechanical signals - Answer-E) mechanical signals
The most significant difference between a paracrine and an autocrine is
A) the cell that releases it.
B) the cell that responds to it.
C) the method of transport.
D) the route of transport.
E) There are no differences—they are the same. - Answer-B) the cell that responds
to it.
Neurotransmitters and neurohormones both
A) are released by neurons.
B) affect only cells with a specific receptor.
C) travel in the blood to their target cell.
D) are released by neurons and affect only cells with specific receptors.
E) are produced by all cells. - Answer-D) are released by neurons and affect only
cells with specific receptors.
Why do some normal cells fail to respond to a chemical signal?
A) Chemical signals are only delivered to specific cells.
B) Some cells lack the necessary receptors.
C) Some cells are completely without receptors.
D) Some cells are completely without ligands.
E) Signal chemicals often break down before reaching a distant target. - Answer-B)
Some cells lack the necessary receptors.
Receptor molecules on the surface of a cell
A) determine that cell's response.
B) may allow a particular ligand to bind.
C) bind to all ligands.
D) determine that cell's response and may allow a particular ligand to bind.
, E) determine that cell's response and bind to all ligands. - Answer-D) determine that
cell's response and may allow a particular ligand to bind.
Receptor molecules are located
A) only in the outer cell membrane.
B) only in the cytosol.
C) only in the nucleus.
D) only on the cell surface.
E) in all of these places. - Answer-E) in all of these places.
Down-regulation may allow a target cell to
A) only increase its number of receptors for a ligand.
B) only decrease its number of receptors for a ligand.
C) only increase its binding affinity for a ligand.
D) decrease the receptors' binding affinity and increase its number of receptors. -
Answer-B) only decrease its number of receptors for a ligand.
Inositol triphosphate
A) is a water-insoluble messenger molecule.
B) binds to the calcium channel of the endoplasmic recticulum.
C) is involved in the release of calcium into the cytosol.
D) is a second messenger that is involved in the release of calcium into the cytosol.
E) uses all of the mechanisms. - Answer-D) is a second messenger that is involved
in the release of calcium into the cytosol.
Lipophilic hormones
A) bind to receptors on the surface of the cell.
B) function by way of a second messenger system.
C) cannot diffuse through the cell membrane.
D) bind to receptors inside the cytoplasm or nucleus.
E) function by activating cAMP. - Answer-D) bind to receptors inside the cytoplasm
or nucleus.
When adenylyl cyclase is activated,
A) calcium ions are released from intracellular stores.
B) cAMP is formed.
C) cAMP is broken down.
D) protein kinases are metabolized.
E) steroids are produced. - Answer-B) cAMP is formed.
Second messenger molecules directly
A) change the regulation of ion channels.
B) increase intracellular calcium concentration.
C) change enzyme activity.
D) change regulation of gene expression.
E) All of the answers are correct. - Answer-E) All of the answers are correct.
Cyclic AMP activates
A) a G protein.
B) adenylyl cyclase.
Questions and Answers
usually called
A) responders.
B) receivers.
C) targets.
D) contacts.
E) junctions - Answer-C) targets.
Which is NOT a basic method of cell-to-cell communication?
A) cytoplasmic transfer of signals
B) contact-dependent signals
C) diffused chemical signals
D) nerve and blood-transported signals
E) mechanical signals - Answer-E) mechanical signals
The most significant difference between a paracrine and an autocrine is
A) the cell that releases it.
B) the cell that responds to it.
C) the method of transport.
D) the route of transport.
E) There are no differences—they are the same. - Answer-B) the cell that responds
to it.
Neurotransmitters and neurohormones both
A) are released by neurons.
B) affect only cells with a specific receptor.
C) travel in the blood to their target cell.
D) are released by neurons and affect only cells with specific receptors.
E) are produced by all cells. - Answer-D) are released by neurons and affect only
cells with specific receptors.
Why do some normal cells fail to respond to a chemical signal?
A) Chemical signals are only delivered to specific cells.
B) Some cells lack the necessary receptors.
C) Some cells are completely without receptors.
D) Some cells are completely without ligands.
E) Signal chemicals often break down before reaching a distant target. - Answer-B)
Some cells lack the necessary receptors.
Receptor molecules on the surface of a cell
A) determine that cell's response.
B) may allow a particular ligand to bind.
C) bind to all ligands.
D) determine that cell's response and may allow a particular ligand to bind.
, E) determine that cell's response and bind to all ligands. - Answer-D) determine that
cell's response and may allow a particular ligand to bind.
Receptor molecules are located
A) only in the outer cell membrane.
B) only in the cytosol.
C) only in the nucleus.
D) only on the cell surface.
E) in all of these places. - Answer-E) in all of these places.
Down-regulation may allow a target cell to
A) only increase its number of receptors for a ligand.
B) only decrease its number of receptors for a ligand.
C) only increase its binding affinity for a ligand.
D) decrease the receptors' binding affinity and increase its number of receptors. -
Answer-B) only decrease its number of receptors for a ligand.
Inositol triphosphate
A) is a water-insoluble messenger molecule.
B) binds to the calcium channel of the endoplasmic recticulum.
C) is involved in the release of calcium into the cytosol.
D) is a second messenger that is involved in the release of calcium into the cytosol.
E) uses all of the mechanisms. - Answer-D) is a second messenger that is involved
in the release of calcium into the cytosol.
Lipophilic hormones
A) bind to receptors on the surface of the cell.
B) function by way of a second messenger system.
C) cannot diffuse through the cell membrane.
D) bind to receptors inside the cytoplasm or nucleus.
E) function by activating cAMP. - Answer-D) bind to receptors inside the cytoplasm
or nucleus.
When adenylyl cyclase is activated,
A) calcium ions are released from intracellular stores.
B) cAMP is formed.
C) cAMP is broken down.
D) protein kinases are metabolized.
E) steroids are produced. - Answer-B) cAMP is formed.
Second messenger molecules directly
A) change the regulation of ion channels.
B) increase intracellular calcium concentration.
C) change enzyme activity.
D) change regulation of gene expression.
E) All of the answers are correct. - Answer-E) All of the answers are correct.
Cyclic AMP activates
A) a G protein.
B) adenylyl cyclase.
