flash cards signaling1_v2

Question 1

If you want to change cocnentration of an extracellualr signal, what do you change?

Answer 1

the degradation rate since this is usually constant

Question 2

binding of lgiand to cellualr protein is a noncovalent or covalent?

Answer 2

noncovalent

Question 3

Non-covalent binding of a ligand to a receptor induces a change in the receptor what of the receptor? What does this trigger?

Answer 3

conformation\n, which then triggers changes in other molecules inside the cell.

Question 4

Receptor conformational change results in either a change in what?

Answer 4

activity, if the receptor is an\nenzyme\n\nchange in affinity for another molecule, if the receptor lacks enzymatic activity.

Question 5

large increase in the concentration of some intracellular second messenger molecule has waht result to the signal?

Answer 5

it amplifies it signal.

Question 6

Amplification is important because:

Answer 6

NAME?

Question 7

the concentration of a signaling molecule depends upon what rates?

Answer 7

the rate of which new molecules appear and the rate at which they are removed

Question 8

in regards to concentration, what rate is usually constant for a signaling molecule?

Answer 8

rate of degradation

Question 9

Rapid changes in signal strength require a short or long signal half-life? fast or slow degadation?

Answer 9

short or fast removal through degradation

Question 10

Steroid hormones generally have long or short half-lives? Do they change concentration slowly or quicly

Answer 10

long half lives\n\nchange concentration gradually

Question 11

peptide hormones have short or long half lifes? do they change concentration short or gradually?

Answer 11

short\n\nquickly

Question 12

Cellular responses to a particular signal depends on what factors?

Answer 12

NAME?

Question 13

Long-term changes in signaling molecule concentration often causes what phenomena?

Answer 13

cell adaptation.

Question 14

a cell may down regulate or upregulate expression of a hormone receptor gene after hormone levels have been high for a prolonged time?

Answer 14

down-regulate

Question 15

Adaptation is a change in the cell’s responsiveness to what

Answer 15

reeptor concentration.

Question 16

how do cells accomplish adaption

Answer 16

the number of available receptors, the affinity of the receptor for its ligand, or the response sensitivity of second messenger pathways to receptor activation.

Question 17

fewer receptors means a less or more sensitive cell

Answer 17

less

Question 18

lower or higher affinity receptor means less sesntiive cell

Answer 18

lower

Question 19

Smaller response to receptor occupancy means a less or a more sensitive cell

Answer 19

less

Question 20

why dont all cells respond simialrly to same ligand

Answer 20

1 cellr esponses depend on specific receptor expressed \n2 cells receive many signals at same time which can cause comeptition or sitmulation of same pathway amploifying signal \n3 some cell responses are all or none \n4 a steep activation curve may prevent reponse untilt threshold is reched

Question 21

Each cell integrates information from how many different signals

Answer 21

many

Question 22

One signal can bind to different what in different cells.

Answer 22

receptors

Question 23

The same type of receptor can activate different what in different cells.

Answer 23

second messengers

Question 24

Two signaling molecules may act through the same second messenger, so that a boost in the concentration of one signal may have what effect?

Answer 24

makes the cell more sensitive to the other one.

Question 25

ignals may pass directly from cell to cell\nthrough gap junctions, but\nmore usually the signaling\nmolecules come from where?

Answer 25

outside\nof the cell.

Question 26

Autocrine,\nparacrine, and synaptic\nsignaling occur over short or long\ndistances.

Answer 26

short

Question 27

endocrine signals are\ncarried through the\nbloodstream

Answer 27

Endocrine

Question 28

Very low\nconcentrations, typical of\nendocrine signals,\nrequire high affinity or low affinity receptors,

Answer 28

high-affinity

Question 29

neurotransmitters are\nprovided at high or low\nconcentrations in the synaptic cleft to low affinity receptors on post-synaptic target cells.

Answer 29

high concentrations

Question 30

Small, rapidly diffusible molecules such as NO and CO pass into cells and do what?

Answer 30

alter enzyme directly

Question 31

small rapidly diffusable moelcues like NO and CO have ___ half lives

Answer 31

very short

Question 32

in pathway of NO action, erve does not directly act on the smooth muscle cell, but instead acts on

Answer 32

endothelial cells that line the lumen of the blood vessel.

Question 33

NO then diffuses out of the endothelial cell and into the smooth muscle cell, where it binds to what? What does this receptor function to do?

Answer 33

adenyl cyclase\n\nconverts gtp to gdp

Question 34

Nitroglycerin prevents heart attacks because it is metabolized to what? How does that substance work?

Answer 34

Nitric oxide, \nwhich dilates blood vessels by activating guanylate cyclase which increases cGMP concentration, and relaxing the smooth muscle in arteriole walls.

Question 35

what is the mechanism of viagra

Answer 35

relaxes smooth muscles and acts as a vasodilator by inhbiitng cGMP breakdnow

Question 36

Hydrophobic molecules such as steroid, retinoids, and through hormones are usually carried by what in the blood?

Answer 36

by binding proteins

Question 37

steroids, retainoids, thyroid hormones pass directly through cell membranes to bind to

Answer 37

cytoplasmic or nuclear receptors of the steroid hormone or nuclear receptor family

Question 38

hydrophobic molecules classified as eicosinoids are derived from phospholipids and include what substances?

Answer 38

prostaglandins, prostacyclins, leukotrienes and thromboxanes.

Question 39

Typical function of eicosinoids are are in what mechanisms?

Answer 39

inflammatory responses and blood clotting.

Question 40

although lipid solbule, eicosnoids bind to what receptors? do they go theough the mebrane?

Answer 40

surface receptors\n\n

Question 41

Steroidal anti-inflammatories like cortisone inhibit synthesis of eicosinoids by inhbiting what?

Answer 41

phospholipase A2.

Question 42

eiconsoids have short or long half lifes

Answer 42

short

Question 43

What is inhibited by aspirin and other non-steroidal anti-inflammatory drugs

Answer 43

Cyclooxygenase

Question 44

hydrolphilic molecules like peptides and nucleotide and amino aic derivatives have short or long half lives

Answer 44

short

Question 45

examples of peptide signaling molecules.

Answer 45

Insulin, glucagon, oxytocin, and erythropoietin

Question 46

Acetycholine, histamine, serotonin and glutamate are examples of small

Answer 46

hydrophilic signaling molecules.

Question 47

Most sensory receptors are ___ molecules.

Answer 47

cell surface

Question 48

Nuclear receptors activate what?

Answer 48

gene transcription.

Question 49

What provide diversity and specific to ncuelar receptors?

Answer 49

a ncuelar receptor super family with DNA binding and hormone binding domains

Question 50

Each DNA binding domain of ncuelar receptor protein recognizes a specific DNA sequence, but actual binding of most nuclear receptors requires what process?

Answer 50

dimerization

Question 51

Many ncuelar receptors form heterodimers with other transcription factors which contributes what?

Answer 51

contribute to the DNA binding specificity and thus the gene activation specificity.

Question 52

Activation of a receptor in two different cell types may activate different patterns of genes because

Answer 52

the receptor dimerizes with a different partner.

Question 53

Genes activated by the hormone-occupied receptor are called what?

Answer 53

primary response genes.

Question 54

What may the roducts of some primary-response genes activate

Answer 54

transcription of secondary response genes

Question 55

What are the four main types of surface receptors Hydrophilic signals act through? What do they each typically intiate?

Answer 55

Ligand-gated ion channels, Enzyme-linked receptors, Catalytic receptors, Trimeric G-protein-linked receptors. \n\nEach initate a second messender sacade

Question 56

What are the different ways ions channels may be gated?

Answer 56

voltage-gated, mechanically gated, or gated by extracellular ligands (primary signals) or intracellular ligands (second messengers).

Question 57

diversity of ion channel selectiveity

Answer 57

some are highly selective like only letting mg in, others have broad specifity for anions or cations

Question 58

What gated ion channel is common in synapthetic signallng pathways

Answer 58

ligand gated

Question 59

G-protein-linked receptors act through direct association with one of several trimeric or monormeric G-proteins.

Answer 59

trimeric

Question 60

G-proteins are ___ that act as switches and can activate or inhibit one or more intracellular signaling pathways.

Answer 60

GTPases

Question 61

The most common enzyme-linked receptors are what type of receptor?

Answer 61

stimulate membrane- associated tyrosine-specific protein kinases such as the serc kinase

Question 62

do enzyme linked receptors themselves have enzyme activity

Answer 62

no

Question 63

Catalytic receptors have domains where that act as enzymes when a ligand binds to the extracellular domain.

Answer 63

cytoplasmic domains

Question 64

catalytic receptors include

Answer 64

serine/threonine kinases, tyrosine kinases, phosphatases, and guanylate cyclases.

Question 65

If a signal has a long half life does it have slow or fast changes in concentration?

Answer 65

slow changes

Question 67

Where are steroid hormone receptors?

Answer 67

intracellular, ligands bind in the cyptosplasm then trasnduce signals in the nculeus

Question 68

what are two drugs which inhbitis eicosinoid synthesis?

Answer 68

aspirin and cortisone

Question 69

What side of the plasma membrane do hyrdophilic moelcules like peptides bind to receptors?\n

Answer 69

they bind to cell surface receptors

Question 70

What is a common mechanism to many but not all nculear receptor family genes?

Answer 70

nuclear translocation