9.5 Signal transduction through G-protein coupled receptors

Question 1

largest category of receptor type in animal cells

Answer 1

G-protein coupled receptors

Question 2

G-protein coupled receptors function through activation of

Answer 2

G-proteins

Question 3

function of G-proteins

Answer 3

provide a link between a receptor and effector proteins

Question 4

what do effector proteins do

Answer 4

produce cellular responses

Question 5

All G-proteins are active when

Answer 5

bound to GTP

Question 6

All G-proteins are inactive when

Answer 6

bound to GDP

Question 7

active G-proteins dissociate into

Answer 7

Gα bound to GTP and Gβγ

Question 8

how does the α subunit inactivate the G protein

Answer 8

hydrolyzes GTP back to GDP

Question 9

effector proteins produce

Answer 9

second messengers

Question 10

2 common effector proteins

Answer 10

adenylyl cyclase and phospholipase C

Question 11

what second messengers do adenylyl cyclase and phospholipase C produce

Answer 11

cAMP, and IP3 plus DAG

Question 12

cyclic AMP is produced by

Answer 12

adenylyl cyclase

Question 13

binds to/activates the enzyme protein kinase A (PKA)

Answer 13

cyclic AMP

Question 14

function of protein kinase A

Answer 14

adds phosphates to specific proteins in the cell

Question 15

inositol phospholipids produce

Answer 15

inositol phosphates

Question 16

most common inositol phospholipid

Answer 16

PIP2

Question 17

PIP2 is cleaved by phospholipase C to yield

Answer 17

DAG plus IP3

Question 18

DAG can activate

Answer 18

protein kinase C (PKC)

Question 19

Calcium ions serve as

Answer 19

secondary messengers

Question 20

intracellular (cytoplasmic) levels of calcium ions are

Answer 20

low

Question 21

extracellular (endoplasmic reticulum) levels of calcium ions are

Answer 21

high

Question 22

the release of calcium ions is triggered by

Answer 22

IP3 binding to channel-linked receptors in the endoplasmic reticulum

Question 23

a versatile cytoplasmic protein

Answer 23

calmodulin

Question 24

calcium ions bind to calmodulin to activate

Answer 24

other proteins and produce a variety of responses

Question 25

different receptors can produce

Answer 25

the same second messengers

Question 26

receptor subtypes can lead to

Answer 26

different effects in different cells

Question 27

different isoforms activate different ___ which lead to different signal transduction pathways

Answer 27

G proteins

Question 28

G protein receptors and receptor tyrosine kinases can both activate

Answer 28

the MAP kinase cascade and phospholipase C