Exam 2 Chapter 15 (Practice Questions)

Front 1

Nitric oxide and ________ are needed to relax the smooth muscle cells of the bloodvessels.

Back 1

Acetylcholine

Front 2

________could be eliminated as a needed signal to relax smooth muscle cells if a membrane permeable cGMP was used.

Back 2

Nitric oxide

Front 3

Cells of many multicellular animals communicate directly by coupling their cytoplasmsusing ________ junctions.

Back 3

Gap

Front 4

Signals that act on the same cells as those that generated them are called ________.

Back 4

Autocrine

Front 5

Signals that diffuse to other types of cells are called ________.

Back 5

Paracrine signals

Front 6

The molecule that binds to the receptor is called a ________.

Back 6

Ligand

Front 7

Phosphatidyl inositol is a ________.

Back 7

Lipid

Front 8

A signal pathway is A) the path a signal takes to find its target cell. B) a group of signals along a concentration gradient. C) the coordinates created from concentration gradients that tell cells where they arelocated in multicellular organisms. D) the series of events that occur in response to a signal being detected. E) a nerve propagation.

Back 8

D

Front 9

In general, all cell signaling causes A) altered gene expression. B) influx of ions. C) protein kinase activity. D) G protein activation. E) a change in receptor conformation.

Back 9

E

Front 10

The major categories of signal receptors are A) inside and outside. B) enzyme and ion channel. C) transmembrane and cytoplasmic. D) protein kinase and cAMP. E) sensory and molecular.

Back 10

C

Front 11

Steroids bind A) to the outer face of transmembrane proteins. B) to cytoplasmic receptors. C) within the lipid bilayer. D) around the nuclear membrane. E) directly to DNA.

Back 11

B

Front 12

Steroids typically affect A) gene transcription. B) ion channels. C) enzyme activity. D) biochemical pathways. E) aggression.

Back 12

A

Front 13

Typically, large polar signals directly interact with A) cytosolic receptors. B) transmembrane receptors. C) G proteins. D) adenylyl cyclase. E) calmodulin.

Back 13

B

Front 14

Insulin is a(n) A) transmembrane protein kinase. B) intracellular signaling molecule. C) form of sugar. D) extracellular ligand. E) derivative of glucose.

Back 14

D

Front 15

Some signal receptors are A) ion channels. B) protein kinases. C) G protein-linked. D) DNA binding proteins. E) All of the above

Back 15

E

Front 16

Different cell types that respond to a certain signal do not all respond the same waybecause A) different types of cells might have different signal pathways for the same signal. B) different cells have different metabolic needs. C) not all cells respond to all signals. D) the cell might have already received the signal previously. E) None of the above

Back 16

A

Front 17

Protein kinase is A) an enzyme that makes cAMP. B) the enzyme that makes cGMP. C) the substrate molecule for kinase. D) an enzyme that phosphorylates. E) None of the above

Back 17

D

Front 18

One of the substrates for protein kinase is A) cAMP. B) cGMP. C) G proteins. D) ATP. E) GTP.

Back 18

D

Front 19

In eukaryotic cells, a substrate for phosphorylation is A) cAMP. B) cGMP. C) specific tyrosines in target proteins. D) specific glycines in target proteins. E) All of the above

Back 19

C

Front 20

Insulin alters cellular metabolism by A) binding with two receptor subunits on the outer cell surface. B) alerting cells about the availability of glucose. C) kinase activity. D) G protein activation. E) opening glucose channels in the membrane.

Back 20

A

Front 21

The insulin receptor is a A) G protein. B) cAMP molecule. C) kinase. D) phosphodiesterase. E) phosphatase.

Back 21

C

Front 22

The receptor-associated proteins called G proteins A) bind GTP. B) are bound to GDP. C) interact with membrane-associated internal proteins to influence their function. D) A and B E) All of the above

Back 22

D

Front 23

The Ras protein is A) a G protein. B) a protein that activates a kinase. C) part of a pathway called a phosphorylation cascade. D) the cause of a certain cancer when it is defective. E) All of the above

Back 23

E

Front 24

In order for a G protein to play its part at moving events forward in a signal pathway, A) GDP must be released and a GTP must occupy the nucleotide-binding site. B) GTP must be released and a GDP must occupy the nucleotide-binding site. C) cGMP must occupy the otherwise empty nucleotide-binding site. D) cGMP must leave the otherwise occupied nucleotide-binding site. E) the G protein must interact with a receptor protein.

Back 24

A

Front 25

If a G protein was unable to release its bound nucleotide but was able to hydrolyze it,signal transduction would A) not move beyond this point. B) be continuous beyond this point. C) be unaffected. D) be constantly switching on and off. E) be unpredictable.

Back 25

A

Front 26

If a G protein was able to release its bound nucleotide but was unable to hydrolyze it,signal transduction would A) not move beyond this point. B) be continuous beyond this point. C) be unaffected. D) be constantly switching on and off. E) be unpredictable.

Back 26

B

Front 27

In heart muscles, the G protein that associates with the epinephrine receptor A) inhibits adenylate cyclase. B) activates adenylate cyclase. C) causes a rise in cGMP. D) causes a decline in cGMP. E) None of the above

Back 27

B

Front 28

In smooth muscle cells of the blood vessels, the G protein that associates with theepinephrine receptor A) inhibits adenylate cyclase. B) activates adenylate cyclase. C) causes a rise in cGMP. D) causes a decline in cGMP. E) None of the above

Back 28

A

Front 29

Cytoplasmic receptors are used for A) epinephrine. B) cAMP. C) steroids. D) insulin. E) All of the above

Back 29

C

Front 30

Cytoplasmic receptors are or are closely associated with A) ligands. B) G proteins. C) transmembrane receptors. D) the endoplasmic reticulum. E) DNA binding proteins.

Back 30

E

Front 31

When a cell with a steroid receptor is exposed to that steroid, the one thing certain tohappen is that the A) receptor will change shape upon binding the steroid. B) cell will produce much more of a muscle cell protein, actin. C) cell will be masculinized. D) cell will be feminized. E) cell will get switched to an "on" state.

Back 31

A

Front 32

Transducers A) change signals from one form to another. B) alter gene expression. C) are simple switches. D) pass a certain signal forward. E) All of the above

Back 32

A

Front 33

The molecule cAMP is called A) coupled adenine monophosphate. B) a signal molecule. C) a second messenger. D) adenylyl adenylate cyclase. E) cyclase adenylyl-phosphate.

Back 33

C

Front 34

Imagine that it is found that the membrane is necessary for a signal to elicit its effect, but it need be present only after signal and cytoplasm have been incubated together. If the experimenter removes the signal from the cytoplasm before adding the membrane, the effect can still be detected. Which of the following conclusions is consistent with theseobservations? A) The signal interacts with a cytoplasmic receptor. B) The signal pathway involves an interaction with a membrane-associated component. C) The signal is unnecessary, but the membrane is necessary. D) The signal pathway starts at the membrane and then progresses into the cytosol. E) A and B

Back 34

E

Front 35

There are analogs to cAMP, which can pass through a membrane unimpeded. If youadded this form of cAMP to liver cells, what would you expect to happen? A) The same events that would occur if you added epinephrine. B) The cell would open its Na+ channels. C) The receptor-associated G protein would activate. D) The receptor-associated G protein would inactivate because it is what normallycauses the elevated cAMP. E) Adenylyl cyclase would activate.

Back 35

A

Front 36

Adenylate cyclase A) is a cyclic nucleotide. B) produces a cyclic nucleotide. C) produces a G protein. D) is a protein kinase. E) is a second messenger molecule.

Back 36

B

Front 37

There are analogs to cAMP, which can pass through a membrane unimpeded. If you added this form of cAMP to odorant receptor nerve cells, what would you expect tohappen? A) The same events that would occur if you added epinephrine. B) The cell would open its Na+ channels. C) The receptor associated G protein would activate. D) The receptor associated G protein would inactivate because it is what normallycauses the elevated cAMP. E) The cAMP is odorless, so nothing would happen.

Back 37

B

Front 38

The concentration of cAMP in a cell is increased by a(n) A) phosphodiesterase. B) cGMP. C) protein kinase. D) ion channel. E) G protein.

Back 38

E