Cellular communication 2

Question 1

Eicosanoids are derived from

Answer 1

polyunsaturated fatty acids

Question 2

The main precursor to eicosanoids is

Answer 2

arachidonic acid

Question 3

Eicosanoids have primarily __________ & _____________actions

Answer 3

autocrine & paracrine actions

Question 4

Unlike steroids, eicosanoids usually bind to

Answer 4

cell surface receptors

Question 5

Eicosanoids are ___________ in the producing cells

Answer 5

Not stored

Question 6

Miscellaneous lipophilic chemical messengers bind to

Answer 6

cytoplasmic or nuclear receptors

Question 7

Examples of peptide and protein chemical messengers include

Answer 7

posterior pituitary- vasopressin, oxytocin
anterior pituitary- FSH, TSH, GH, LH
Kidneys- renin, erythropoietin
etc.

Question 8

Peptide and protein chemical messengers are generally

Answer 8

polar (hydrophilic) molecules

Question 9

Peptide and protein chemical messengers do not

Answer 9

readily cross plasma membranes- usually bind to cell surface receptors

Question 10

Peptide and protein chemical messengers circulate in

Answer 10

the bloodstream as unbound molecules

Question 11

The subclasses within other chemical messengers include

Answer 11

nucleotides and nucleosides: adenosine & ATP
gases: nitric oxide, carbon monoxide
endocannabinoids: anandamide, 2-arachidonylglycerol

Question 12

Adenosine and ATP are

Answer 12

purines

Question 13

Nucleotides and nucleosides are not stored

Answer 13

in vesicles

Question 14

CO and NO are

Answer 14

lipid-soluble molecules with paracrine actions

Question 15

NO is synthesized from the

Answer 15

amino acid L-arginine

Question 16

Both CO & NO serve as

Answer 16

retrograde neurotransmitters

Question 17

Endocannabinoids are derived from

Answer 17

arachidonic acide

Question 18

Endocannabinoids bind to _____________ receptors

Answer 18

CB-1 (CNS) and CB-2 (peripheral)

Question 19

Endocannabinoids are _________________ but, they bind to

Answer 19

liphophilic; cell-surface receptors

Question 20

Which categories of signaling molecules are stored in vesicles in the cell that synthesized the molecules?

Answer 20

small hydrophilic chemical messengers
peptide and protein chemical messengers

Question 21

Which lipophilic chemical messengers are not derived from cholesterol?

Answer 21

eicosanoids
retinoids
endocannabinoids

Question 22

Dopamine, Epi, NE, and the iodohtyronines are derived from which amino acid?

Answer 22

tyrosine

Question 23

How many times does a G protein-coupled receptor span the plasma membrane?

Answer 23

7 times

Question 24

______________ represent the largest and most diverse family of receptors on the cell surface

Answer 24

G protein-coupled receptors

Question 25

G protein-coupled receptors are important in anesthesia b/c

Answer 25

1/2 to 2/3rds of all drugs target them

Question 26

A diverse array of signaling chemicals that bind to GPCRs include

Answer 26

neurotransmitters
hormones
vasoactive peptides
odorants
tastants
local chemical factors

Question 27

G proteins are molecular

Answer 27

switches and can inactivate themselves through inherent GTPase activity in the alpha subuint

Question 28

What are the four G protein families?

Answer 28

Gs (“s” is for stimulatory)
Gi (“i” is for inhibitory)
Gq (no specific meaning for “q”)
G12, 13

Question 29

What is the overall sequence of signal transduction through G protein-coupled receptors?

Answer 29

First messenger (ligand)–> GPCR–> effector–> second messenger–> cellular response

Question 30

What are the three essential components that signal transduction through GPCRs?

Answer 30

a plasma membrane receptor with 7 transmembrane segments
G protein activates the effector enzyme or pathway
an effector generates an intracellular second messenger

Question 31

G proteins are turned ON when

Answer 31

a ligand binds to the receptor-binding site

Question 32

G proteins are turned OFF by

Answer 32

the intrinsic GTPase activity in the alpha subunit

Question 33

GDP is bound to the

Answer 33

alpha subunit of the GPCR

Question 34

The GPCR conformational change facilitates the release of

Answer 34

bound GDP and simultaneous binding of GTP to the alpha subunit

Question 35

The first messenger signal at the G protein coupled receptor is terminated by:

Answer 35

diffusion of the ligand away from the receptor
chemical modification of the receptor to desensitize the receptor

Question 36

The Gs alpha-s subunit stimulates

Answer 36

adenylyl cyclase
Gi (inhibits adenylyl cyclase)

Question 37

Gq stimulates

Answer 37

phospholipase C

Question 38

G12,13 activates

Answer 38

small G proteins

Question 39

Cholera toxin chemically alters the

Answer 39

Gs subunit to inhibit the intrinsic GTPase activity
ends up stimulating the export of fluid across the interstitial epithelium

Question 40

Pertussis toxin chemically alters the

Answer 40

Gi0 subunits,
leads to accumulation of cAMP

Question 41

McCune-Albright syndrome is characterized by

Answer 41

defects of hormonal regulation

Question 42

The McCune-Albright syndrome is caused by a

Answer 42

gain-of-function mutation of Gs that correlates with disturbance of Gs-controlled hormone production

Question 43

Pseudohypoparathyroidism is caused by a

Answer 43

loss-of-function mutation of Gs

Question 44

The effects of pseudohypoparathyroidism leads to

Answer 44

premature puberty with obesity, growth retardation, and skeletal deformities

Question 45

Major effectors targets of Ga subunits include:

Answer 45

adenylate cyclases
phospholipase C
phospholipase A2

Question 46

Major effector targets of GBy subunits include:

Answer 46

Gi0-regulated potassium channels
voltage-gated calcium channels
B-adrenergic receptor kinase (BARK)