Cellular communication 7

Question 1

Platelet aggregation is induced by ADP binding to

Answer 1

P2YRs

Question 2

ALL neuropeptides act on ____________ receptors and most often induce alterations in the _______________

Answer 2

metabotropic receptors; alteration in the excitability of postsynaptic cells

Question 3

Nitric oxide acts as a ___________________________ signaling molecule

Answer 3

autocrine and paracrine

Question 4

Generation of NO requires

Answer 4

NADPH
molecular oxygen
& is catalyzed by a family of oxygenases known as NO synthases

Question 5

What are the three families of nitric oxide synthase?

Answer 5

NOS1 also called cNOS or nNOS
NOS2 of iNOS
NOS3 also known as eNOS

Question 6

NOS1 & NOS3 are __________-dependent enzymes

Answer 6

calcium

Question 7

NO effects depend on its

Answer 7

tissue concentration

Question 8

At low concentrations, NO functions as a

Answer 8

signaling molecule and interacts with a cytoplasmic receptor

Question 9

At higher concentrations, NO exhibits

Answer 9

signaling effects by modifying proteins by nonenzymatic S-nitrosylation

Question 10

At even higher concentrations, _____________ effects of NO dominate

Answer 10

cytotoxic effects

Question 11

NO facilitates

Answer 11

sleep
contributes to normal feeding behavior
has a role in GI function

Question 12

____________________ is an activity-dependent increase in synaptic efficacy

Answer 12

Long-term potentiation

Question 13

_________________ is a decrease in synaptic efficacy due to prolonged “weak” stimulation of a synapse

Answer 13

Long-term depression

Question 14

Are GTP and ATP classified as purines or pyrimidines?

Answer 14

purines

Question 15

What enzyme converts ATP to adenosine in the synaptic cleft?

Answer 15

ectonucleotidase

Question 16

Are all neuropeptide receptors ionotropic or metabotropic?

Answer 16

metabotropic

Question 17

What signaling complex activates nNOS?

Answer 17

Ca2+/CaM (calmodulin)

Question 18

What cytosolic heme-containing enzyme is activated by NO?

Answer 18

soluble guanylyl cyclase (sCG)

Question 19

The receptor for insulin is a:
a. receptor guanylyl cyclase
b. receptor tyrosine kinase
c. tyrosine kinase-associated receptor
d. receptor serine/threonine kinase

Answer 19

b. receptor tyrosine kinase

Question 20

What are the five major categories of enzyme-linked receptors?

Answer 20

receptor guanylyl cyclases
receptor tyrosine kinases
tyrosine kinase-associated receptors
receptor serine/threonine kinases
receptor tyrosine phosphatases

Question 21

Receptor ________________- converts GTP to cGMP.

Answer 21

guanylyl cyclases

Question 22

______________ are the largest family of enzyme-linked receptors

Answer 22

receptor tyrosine kinases

Question 23

These are ligands to receptor tyrosine kinases:

Answer 23

insulin & growth factors

Question 24

Mutations in receptor tyrosine kinases are associated with

Answer 24

a wide variety of cancers

Question 25

Tyrosine kinase-associated receptors do not have

Answer 25

intrinsic enzyme activity

Question 26

_______________________ are important mediators of cell growth and differentiation.

Answer 26

receptor serine/threonine kinases

Question 27

The following are ligands for receptor guanylyl cyclase:

Answer 27

ANP
BNP
CNP (C-type natriuretic peptide)

Question 28

___________________, a recombinant version of native natriuretic peptides, is used in the treatment of decompensated heart failure

Answer 28

Nesiritide

Question 29

The ligands for receptor tyrosine kinases are

Answer 29

hormones such as insulin and various growth factors

Question 30

The insulin receptor is present on most tissues, but the energy-storing tissues ________, _________, and ________ express higher levels of the receptor and have greater responses to insulin.

Answer 30

liver, muscle, & adipocytes

Question 31

Ligands with tyrosine kinase-associated receptors are

Answer 31

cytokines, including many interleukins, interferons, erythropoietin, growth hormone, prolactin, and leptin

Question 32

This receptor is associated with the JAK-STAT downstream receptor

Answer 32

tyrosine kinase-associated receptors

Question 33

This receptor is responsible for cell-differentiation

Answer 33

serine-threonine kinase receptors

Question 34

TGF-B is a ligand with this receptor

Answer 34

serine-threonine kinase receptors

Question 35

This is a leptin receptor

Answer 35

tyrosine kinase-associated receptors

Question 36

Which signaling molecules bind to nuclear receptors? (select 3)
a. acetylcholine
b. testosterone
c. vitamin D
d. erythropoietin
e. triiodothyronine
f. gamma-aminobutyric acid

Answer 36

b. testosterone
c. vitamin D
e. triiodothyronine

Question 37

Ligated (ligand-bound) nuclear receptor complexes are activated transcription factors that regulate the

Answer 37

expression of target genes in the DNA

Question 38

The intracellular receptor family includes receptors for

Answer 38

steroid hormones, prostaglandins, vitamin D, thyroid hormones, and retinoic acid

Question 39

____________ increase basal metabolic rate by stimulating futile cycles of catabolism and anabolism

Answer 39

thyroid hormones

Question 40

___________________ are activated transcription factors that bind in a highly specific manner to short DNA sequences called hormone response elements

Answer 40

Ligand-bound nuclear receptors

Question 41

The nuclear receptor family is classically divided into two subfamilies:

Answer 41

receptors for steroid hormones
receptors for retinoic acid, thyroid hormone, and vitamin D.

Question 42

Steroid hormone receptors are

Answer 42

homodimers

Question 43

Receptors for retinoic acid, thyroid hormones, and vitamin D form

Answer 43

heterodimers

Question 44

Which specific thyroid hormone occupies the most thyroid receptors in the euthyroid state?

Answer 44

T3 (triiodothyronine)

Question 45

The DNA-binding site for ligand-bound nuclear receptors is called a/n:

Answer 45

hormone response element

Question 46

An unoccupied cytoplasmic intracellular receptor is frequently complexed to a/n:

Answer 46

chaperone protein (heat shock protein)

Question 47

What syndrome is associated with congenital hypothyroidism?

Answer 47

cretinism