Week 7_Cell-cell communication

Question 1

cells that are talking put out…

Answer 1

ligands

Question 2

what are ligands?

Answer 2

signaling molecules that talking cells put out

Question 3

cells that are listening have…

Answer 3

a receptor that the ligand attaches to

Question 4

what does the ligand/receptor complex do?

Answer 4

transmits the signal into the target cell –> the target cell responds

Question 5

___ leads to a cellular response

Answer 5

signal transduction

Question 6

ligand/receptor complex ___ (transmits) the signal into the cell

Answer 6

transduces

Question 7

what are some examples of types of cellular responses?

Answer 7

altered metabolism

altered gene expression

altered cell shape or motility

Question 8

the responding cell is called the ___

Answer 8

target cell

Question 9

does every cell respond to every signal?

Answer 9

no;

only the target cell with the proper receptor will respond to a particular ligand

Question 10

there are ___ categories of cell signaling?

Answer 10

5

Question 11

the 5 categories of cell signaling are based on:

Answer 11

the distance b/n the cells that are communicating

the type of cells that are communicating

Question 12

what are the 5 categories of cell signaling?

Answer 12

autocrine signaling

direct cell-to-cell contact

paracrine signaling

endocrine signaling

synaptic signaling

Question 13

what is autocrine signaling?

Answer 13

cell signaling to itself

Question 14

what are examples of autocrine signaling?

Answer 14

immune cells – stimulate and amplify their own response to infections

cancer cells – stimulate their own growth and mobility

Question 15

elaborate direct cell-to-cell contact

Answer 15

surface ligand on one cell touches surface receptor on the next cell

direct transmission of ligands thru gap junctions b/n cells

Question 16

what are examples of cell-cell interactions?

Answer 16

cell-cell interactions play a critical role during:

embryonic development

wound healing

Question 17

what is paracrine signaling?

Answer 17

cells signaling to nearby cells

Question 18

what are examples of paracrine signaling?

Answer 18

ligands released at injury sites to stimulate an immune response and wound healing

embryonic development – development of the spinal cord

Question 19

what is endocrine signaling?

Answer 19

systemic (organism wide) signaling via the circulatory system

Question 20

what is an example of endocrine signaling?

Answer 20

hormones – released into bloodstream

stimulate development and maintenance of the reproductive system

Question 21

what is synaptic signaling?

Answer 21

signal by a nerve cell thru a synapse to another cell or a responding cell

Question 22

what is an example of synaptic signaling?

Answer 22

neurotransmitters – signaling molecules sent from a nerve cell to another nerve cell or a responding cell (a muscle cell)

Question 23

what are the 2 types of signaling molecules (ligands)?

Answer 23

non-circulating ligands

circulating ligands

Question 24

what are circulating ligands?

Answer 24

circulate thru the blood or other bodily fluids

Question 25

what are the 2 types of circulating ligands?

Answer 25

non polar (hydrophobic) polar (hydrophilic ligands)

Question 26

what are examples of hydrophobic ligands?

Answer 26

hormones - can diffuse across the plasma membrane - hydrophobic ligands bind to intracellular receptors - intracellular receptors transmit the signal - cell responds

Question 27

can hydrophilic ligands diffuse across the plasma membrane?

Answer 27

no; they are polar

Question 28

hydrophilic ligands must bind to ___, which have ___

Answer 28

membrane-bound receptors 3 protein domains

Question 29

what are the 3 protein domains on membrane bound receptors?

Answer 29

(1) an extracellular ligand binding domain (binds to ligand) (2) transmembrane domain (goes thru the plasma membrane) (3) intracellular signaling domain (transduces the signal)

Question 30

many drugs ___ receptors

Answer 30

target (bind to)

Question 31

drugs can be ___ or ___

Answer 31

agonists or antagonists

Question 32

what are agonists?

Answer 32

mimic actions of ligand (activates receptor)

Question 33

what are antagonists?

Answer 33

bind to but do not activate a receptor they block ligands from binding to the receptor

Question 34

what are examples of agonists?

Answer 34

drugs that activate the opioid receptor

Question 35

what is naloxone/narcan?

Answer 35

opioid receptor antagonist outcompetes agonists for binding to the opioid receptor blocks the effects of drugs such as heroine and other opioid agonists

Question 36

other medical uses for receptor antagonists include...

Answer 36

antihistamines beta blockers in cancer therapy

Question 37

what do antihistamines do?

Answer 37

block the activity of histamine receptors to lessen the immune response

Question 38

what do beta blockers do?

Answer 38

block some receptor sites for adrenaline to control blood pressure

Question 39

explain receptor antagonists in cancer therapy?

Answer 39

many cancer therapy drugs that block receptors important to cancer cell growth and metastasis