Question 1

The surface receptors that recognize and bind signaling molecules are ____.

Accepted Answer

A)  glycoproteins 
B)  glycolipids 
C)  phospholipids 
D)  promoters 
E)  ligands

Question 2

In order for a cell to respond to the signaling molecule epinephrine, it must have ____.

Accepted Answer

A)  ion channels 
B)  a lipid bilayer through which epinephrine can pass 
C)  receptors with an epinephrine binding site on the cytoplasmic side of the  plasma membrane 
D)  receptors with an epinephrine binding site on the plasma membrane surface 
E)  nuclear membrane receptors

Question 3

Researchers have determined that the growth of hormone-responsive breast cancer cells depends upon ____.

Accepted Answer

A)  the relative concentrations of ERα and ERβ in the tumor cells 
B)  the ability of ERβ to stimulate cancer cell growth 
C)  the ability of ERα to inhibit cancer cell growth 
D)  whether DNA binding sites exists for ERα, but not ERβ 
E)  the relative concentrations of estrogen and testosterone in breast tissue

Question 4

How does a cell surface receptor respond to the binding of a signaling molecule?

Accepted Answer

A)  The cell surface receptor denatures. 
B)  The signal is transduced through the plasma membrane and into the cell. 
C)  The receptor relays a signal to another location on the cell surface. 
D)  The cell surface receptor flips through the membrane to the inside of the cell. 
E)  Polarization of the cell surface changes.

Question 5

Amplification is an important characteristic of signal transduction pathways involving surface receptors. What is amplification and how is it accomplished in the cell?

Accepted Answer

The answer of Amplification is an important characteristic of signal...

Question 6

Amplification of a signal increases as the ____.

Accepted Answer

A)  number of enzyme-catalyzed steps increases 
B)  number of enzyme-catalyzed steps decreases 
C)  volume of the cell increases 
D)  volume of the cell decreases 
E)  rate of reaction of the rate-limiting reaction increases

Question 7

Hormone receptors are comprised of two domains, the hormone binding domain and the ____, which triggers the cellular response.

Accepted Answer

A)  gene activation domain 
B)  DNA-binding domain 
C)  phosphorylation domain 
D)  kinase domain 
E)  phosphatase domain

Question 8

Acetylcholine, a neurotransmitter, binds to ____.

Accepted Answer

A)  receptor tyrosine kinases 
B)  ligand-gated ion channels 
C)  adenylyl cyclase 
D)  MAPK 
E)  G-coupled protein receptors

Question 9

Cross-talk between second messenger pathways is probably involved in particular types of olfactory signal transduction in many animals.

Accepted Answer

A) True 
 B)False

Question 10

Match between columns
                        Premises: communication used by neurotransmitters acting on neuron across a synapse
paracrine regulation
communication used by cardiac muscle cells to synchronize heart contractions
autocrine regulation
cell communication by direct contact
long-distance signaling
mediation of the fight-or-flight response by epinephrine

Accepted Answer

The Answer of d and a and b and c is...

Question 11

Match between columns
                        Premises: pathway triggered by glucagon to stimulate glycogen breakdown
converts an extracellular signal into an intracellular response
lithium reduces the activity of this pathway
directly bind to DNA to affect transcription
binds to and activates the enzyme guanylyl cyclase
binds to acetylcholine
G protein activated by a receptor tyrosine kinase
defects in this receptor type can lead to diabetes and dwarfism

Accepted Answer

The Answer of cAMP and nitric oxide and hormone receptors is...

Question 12

Protein kinases ____.

Accepted Answer

A)  add phosphate groups to proteins 
B)  bind cGMP 
C)  stimulate adenylyl cyclase 
D)  polymerize amino acids 
E)  hydrolyze proteins

Question 13

In the 1950s, Earl Sutherland and colleagues discovered that epinephrine ____.

Accepted Answer

A)  triggers the release of a second messenger that leads to the hydrolysis of glycogen to glucose 
B)  triggers the release of a second messenger that lowers blood glucose by causing it to bind to liver cells 
C)  interacts directly with the enzyme glycogen phosphorylase 
D)  interacts directly with the cell membrane to help transport glucose into the cell 
E)  is a signaling molecule that does not require a cell surface receptor

Question 14

Ras proteins are of interest to researchers because of their role in ____.

Accepted Answer

A)  reproduction 
B)  linking plant hormones to germination 
C)  the development of many types of cancer 
D)  relieving cluster headaches 
E)  eliciting the fight-or-flight response

Question 15

How does cAMP regulate glucose levels in mammals?

Accepted Answer

The answer of How does cAMP regulate glucose levels in...

Question 16

The effects of protein kinases are reversed by another group of enzymes called ____.

Accepted Answer

A)  hydrolases 
B)  catalases 
C)  isomerases 
D)  phosphatases 
E)  proteases

Question 17

How is the NO pathway manipulated by Viagra to treat erectile dysfunction?

Accepted Answer

A)  NO synthesis is decreased 
B)  NO synthesis is increased 
C)  the enzyme catalyzed by NO is stabilized 
D)  the enzyme catalyzed by NO is inhibited 
E)  the breakdown of cGMP is inhibited

Question 18

Activated Ras ____.

Accepted Answer

A)  activates MAP kinase (MAP K) 
B)  opens a calcium channel 
C)  triggers gene transcription 
D)  binds DNA 
E)  triggers the secretion of growth factors

Question 19

Substance A is secreted by the liver, travels through the circulatory system bound to a carrier protein, and causes a change in gene expression in its target cell. Substance A is therefore a ligand for ____.

Accepted Answer

A)  a receptor tyrosine kinase 
B)  a G-protein-coupled receptor 
C)  a steroid hormone receptor 
D)  a ligand-gated ion channel 
E)  guanylyl cyclase

Question 20

An example of a nonpolar signaling molecule is ____.

Accepted Answer

A)  epinephrine 
B)  insulin 
C)  testosterone 
D)  growth factors 
E)  neurotransmitters

Exam 9: Cell Communication