Signal Transduction Perrino

Question 1

what type of signaling is a process in which one cell creates signaling molecules that is recognized by neighboring target cells

Answer 1

Paracrine signaling

Question 2

what type of signaling is the release of signaling molecules into the blood stream where they can bind to receptors that are far from the sources of release.

Answer 2

Endocrine Signaling

Question 3

synaptic signaling involves a target cell and a (blank) forming a synapse

Answer 3

neuron

Question 4

what type of signaling does not require high affinity ligand binding?

Answer 4

synaptic signaling

Question 5

what type of signaling requires high affinity ligand binding?

Answer 5

endocrine signaling

Question 6

what type of signaling molecule is common in endocrine signaling?

Answer 6

Hormones

Question 7

what is the common “generic” intracellular signaling pathway?

Answer 7

extracellular signaling molecule binds to receptor protein– intracellular signaling protein cascade–effector proteins–resulting in altered metabolism, altered gene expression, or altered cell shape or movement.

Question 8

what are 4 methods cells use for signaling?

Answer 8

cell-surface receptors
contact-dependent
intracellular receptors
gap junctions

Question 9

what type of signaling involves a group of identical signaling cells?

Answer 9

autocrine signaling

Question 10

what type of signaling uses vast distances and a large volume of signaling molecules?

Answer 10

endocrine signaling

Question 11

what type of signaling uses very small distances with a small volume of signaling molecules?

Answer 11

synaptic signaling

Question 12

in which type of signaling is the concentration of signaling molecules very high?

Answer 12

synaptic signaling

Question 13

what do selective serotonin reuptake inhibitors (SSRIs) do?

Answer 13

the act within the brain to increase the amount of Serotonin in the synaptic gap by inhibiting its reuptake.

Question 14

cells are programmed to respond to specific combinations of signaling. what are the 4 different generic signals?

Answer 14

Survive
grow and divide
differentiate
Die

Question 15

what is contact-dependent signaling?

Answer 15

membrane bound signaling molecules directly interact with receptor on adjacent targeted cell.

Question 16

what are two types of molecular switches?

Answer 16

singling by phosphorylation & Signaling by GTP-Binding

Question 17

which molecular switch always turns proteins/pathways on?

Answer 17

GTP-Binding signaling

Question 18

which molecular switch can turn a proteins/pathway on or off?

Answer 18

Signaling by phosphorylation

Question 19

what is the inactive form and the active form in GTP-Binding

Answer 19

GDP-inactive, GTP-active binding

Question 20

phosphorylation requires which high energy molecule to turn something on?

Answer 20

ADP to ATP

Question 21

switches allow for the (blank) of signals

Answer 21

integration

Question 22

what to signaling complexes allow for?

Answer 22

specificity by restricting localization of the integrated signal

Question 23

what allows for the assembly of molecular switch complexes?

Answer 23

modular binding domains of signaling proteins.
ex. RTKs binding with PTB docking proteins which bind with SH2 domains which bind to membrane bound docking sites and other scaffolding proteins.

Question 24

as the number of activator molecules that are bound to the effector protein increase, the slope of the activation curve (blank)

Answer 24

increases

Question 25

describe threshold activation

Answer 25

some effector proteins require binding of multiple signaling molecules in order to reach a level for activation can occur

Question 26

what type of binding is an "all or nothing" response?

Answer 26

threshold activation- no activity is seen during the build up of signaling molecules till the threshold is achieved.

Question 27

what are the 5 mechanisms of desensitization?

Answer 27

``` Receptor sequestration receptor down regulation receptor inactivation inactivation of signaling protein production of inhibitory proteins ```

Question 28

what is receptor sequestration?

Answer 28

receptors are removed from cell membrane and internalized

Question 29

what is receptor down-regulation?

Answer 29

receptor number is decreases via lysosomal degradation.

Question 30

what type of desensitization involves the receptor being inactivated via phosphorylation or binding of another molecule to in intracellular domain?

Answer 30

Receptor- Inactivation

Question 31

what type of desensitization: receptor is activated but the protein within the signaling pathway is inactivated , causing a block in the pathway

Answer 31

inactivation of signaling protein

Question 32

what is the production of inhibitory protein?

Answer 32

another protein inhibits pathway or signaling cascade

Question 33

define positive feedback

Answer 33

product of a reaction or signaling pathway increases its own output.

Question 34

define negative feedback

Answer 34

product formed reduces its formation of more product

Question 35

a ligand binds a substrate activating it, an enzyme than binds increasing its activity, with the addition of yet another enzymes the activity is further increase ( a switch like behavior). This is an example of what?

Answer 35

accelerating positive feedback

Question 36

which type of ligands typically have intracellular receptors?

Answer 36

Steroid hormones

Question 37

what are 2 other important classes of signaling molecules that bind to intracellular receptors?

Answer 37

vitamind D3 and retonic acid

Question 38

steroid hormones are (blank)

Answer 38

transcription factors

Question 39

Rapid responses from signaling transduction most likely include change in (blank)

Answer 39

protein function

Question 40

slow responses (mins to hrs) from signaling transduction most likely include (blank)

Answer 40

altered protein synthesis

Question 41

singling molecules in the circulation are usually carried by what?

Answer 41

carrier proteins- signaling molecules are normally hydrophobic so they pass through cell membrane easily but need help with migration through the circulation.

Question 42

prostaglandins (PGs) synthesis from membrane phospholipids is an example of (blank)

Answer 42

autocrine signaling

Question 43

what to PGs mediate?

Answer 43

pain responses, as in headaches, arthritis, menstrual cramps etc..

Question 44

PG synthesis is inhibited at phospholipase A2 stage by what?

Answer 44

corticosteroids

Question 45

PG synthesis inhibited at cyclooxyhenase stage by what?

Answer 45

NASIDs like ibuprofen

Question 46

what are the stages of prostoglandin synthesis?

Answer 46

membrane phospholips--arachidonic acid (extended)-- arachidonic acid folded confirmation--prostaglandin

Question 47

what are three cell types that can respond to acetylcholine (ACh)

Answer 47

Skeletal muscle cell, heart muscle, salivary gland cell.

Question 48

Nitric Oxide (NO) as an important signaling molecule with an (blank) receptor

Answer 48

intracellular receptor

Question 49

erectile dysfunction medication such as Viagra work by doing what?

Answer 49

inhibiting the breakdown of cyclic GMP by inhibiting phosphodiesterase (PDE) from breaking down cGMP