2.10 Signal Transduction and Second Messengers

Question 1

Conversion of one form of information to another

Usually a biochemical response

Answer 1

Signal transduction

Question 2

Multiplication of an original signal

Answer 2

Signal amplication

Question 3

The signal is meant for specific recipient

Answer 3

Target specificity/selectivity

Question 4

How cells receive, process, and respond to external information

Answer 4

Information metabolism

Question 5

Pathways that mediate the sensing and processing of stimuli

Answer 5

Signal-transduction cascasdes

Question 6

Modes of signaling

Passed into blood for reception in target cells that are distant from the site of creation

Answer 6

Endocrine

Question 7

Modes of signaling

Passed into nearby cellular spaces for action on cells in close proximity to the site of creation

Answer 7

Paracrine

Question 8

Modes of signaling
Transmitted via synapses
For propagation of neural impulses

Answer 8

Neuronal

Question 9

Modes of signaling
Juxtacrine interactions
Bound to the plasma membrane of the signaling cells to interact with a receptor on a directly adjacent cell

Answer 9

Contact-dependent signaling

Question 10

Communication of cells is provided by ____ and ____.

Answer 10

Cell signaling

Transduction

Question 11

5 phases of signal transduction

Answer 11

Signal
Reception
Integration/Adaptation
Amplification
Target

Question 12

Transmit a signal when bound to GTP and are silent when bound to GDP

Answer 12

G proteins

Question 13

Extracellular signaling molecules fall into 2 classes

Answer 13

Cell-surface receptors

Intracellular receptors

Question 14

Intracellular molecules that change in concentration in response to environmental signals

Answer 14

Second messengers

Question 15

Receptors for nitric oxide (NO)

Answer 15

Soluble Guanylyl Cyclases

Question 16

Reactive free-radical that acts either as a neurotransmitter or as a second messenger

Answer 16

Nitric oxide

Question 17

Two types of receptors that are possible for steroid hormones

Answer 17

Intracellular receptors

Membrane bound receptors

Question 18

Can translocate to the nucleus and direct gene expression

May take hours or days

Answer 18

Intracellular receptors

Question 19

Can act on the cellular players with immediate action

Answer 19

Membrane bound receptors

Question 20

The steroid intracellular receptor superfamily are ____

Answer 20

Transcription factors

Question 21

Phases of signal transduction

Answer 21

Signal
Reception
Integration/Adaption (Second messenger)
Amplification (Second messenger)
Target

Question 22

In membrane receptor-mediated signal transduction, ____ is a common means of information transfer

Answer 22

Protein phosphorylation

Question 23

Small hydrophobic signal molecules diffuse directly across the lipid bilayer therefore they bind to intracellular receptors

Answer 23

Intracellular-Receptor-Mediated Signals

Question 24

True or False
Many receptors are kinases or are associated with kinases. Cytokine receptor superfamily is similar to the receptor-tyrosine-kinases and has the same receptors and kinases.

Answer 24

False

Cytokine receptor superfamily has separate receptors and kinases to the receptor-tyrosine-kinases

Question 25

Tyrosine kinases may activate one form of ____, PLC-gamma

Answer 25

Phospholipase C

Question 26

Receptors that usually interact with polar hydrophilic signaling molecules for receiving environmental signals

Answer 26

Cell surface receptors

Question 27

Receptors that interact with nonpolar, hydrophobic signaling molecules, usually for fine tuning signaling within a cell

Answer 27

Intracellular receptors

Question 28

What classification do non-steroid hormones fall under? Why?

Answer 28

Cell surface receptors | Polar and hydrophilic

Question 29

One or more components of one signal transduction pathway affects the another

Answer 29

Cross talk

Question 30

Phases of signal transduction

Answer 30

``` Signal Reception Integration/Adaption (Second messenger) Amplification (Second messenger) Target ```

Question 31

Reactive free radical that relaxes vascular smooth muscles and stimulates macrophages to kill tumor cells and bacteria

Answer 31

Nitric Oxide

Question 32

Small hyprophobic signal molecules diffuse directly across the lipid bilayer therefore they bind to intracellular receptors

Answer 32

Intracellular-Receptor-Mediated Signals

Question 33

The hydrolysis of Phosphatidylinositol bisphosphate by phospholipase C generates how many messengers?

Answer 33

2

Question 34

Calmodulin is activated by the binding of __ ions, when the cytosolic calcium level is raised above 500 nM

Answer 34

Calcium

Question 35

Inositol 1,4,5-triphosphate opens channels to release __ ions from intracellular stores

Answer 35

calcium

Question 36

Two messengers generated by the hydrolysis of phosphatidylinositol bisphosphate

Answer 36

Diacylglycerol | Inositol 1,4,5-triphosphate

Question 37

On hydrolysis of the bound GTP by the intrinsic GTPase activity of Ga, Ga reassociates with the bg subunits to form the heterotrimeric G protein, thereby terminating the activation of ___.

Answer 37

Adenyl cyclase

Question 38

Activates PKC

Answer 38

Diacylglycerol

Question 39

True or False | DAG and IP3 work in tandem

Answer 39

True

Question 40

A 17-kD protein with four calcium-binding sites and a member of the EF-hand protein family

Answer 40

Calmodulin

Question 41

cAMP is degraded by ___

Answer 41

cAMP phosphodiesterase

Question 42

Epinephrine targets a ___ coupled receptor

Answer 42

G-protein

Question 43

True or False | The role of the hormone-bound receptor is to inhibit the exchange of GTP for bound GDP

Answer 43

False | It functions to catalyze, not to inhibit

Question 44

On hydrolysis of the bound GTP by the intrinsic GTPase activity of Ga, Ga reassociates with the bg subunits to form the heterotrimeric G protein, thereby terminating the activation of ___.

Answer 44

Adenyl cyclase

Question 45

Some G proteins regulate membrane bound enzymes to make ___.

Answer 45

Second messengers

Question 46

Converts ATP into cAMP

Answer 46

Adenylyl cyclase

Question 47

Name the 2 separate insulin signaling cascades lead to GLUT4 translocation to the the plasma membrane.

Answer 47

TC10 | PPIn-3 kinase

Question 48

cAMP is degraded by ___

Answer 48

cAMP phosphodiesterase

Question 49

Forms of Cell surface receptors

Answer 49

Ion channel linked Enzyme linked Gprotein

Question 50

Cell surface receptors that are regulated by signaling molecules. Channels are often in neurons and muscles

Answer 50

Ion channel linked receptors

Question 51

Cell surface receptors wherein binding of molecule to receptor either activates the catalytic domain of the receptor or alters the receptor such that it associates with an active cytoplasmic enzyme

Answer 51

Enzyme linked receptors

Question 52

Cell surface receptors that activate g proteins that activate the enzyme or opens the ion channel

Answer 52

G protein receptors

Question 53

General mechanism for Membrane-Receptor Mediated Signals

Answer 53

1) Membrane receptors transfer info from the environment to the cell's interior 2) Second Messengers relay information from the receptor ligand complex 3) Protein phosphorylation (probably, it's common) 4) Termination of signal

Question 54

One or more components of one signal transduction pathway affects the another

Answer 54

Cross talk

Question 55

cAMP activates ___

Answer 55

cAMP-dependent protein kinase (PKA)

Question 56

Phosphorylation of cellular proteins by PKA causes the cellular response to ___

Answer 56

Epinephrine

Question 57

True or False | PKA can phosphorylate enzymes and transcriptional activators

Answer 57

True

Question 58

True or False | Glycogen metabolism is regulated by dephosphorylation of glycogen synthase and glycogen phosphorylase

Answer 58

False

Question 59

PKA can phosphorylate __ channels to close them, which increases the excitability of the target cell.

Answer 59

Potassium

Question 60

Name the 2 separate insulin signaling cascades that lead to GLUT4 translocation to the plasma membrane.

Answer 60

TC10 | PPIn-3 kinase

Question 61

Cholera and whooping cough are due to altered __ activity.

Answer 61

G-protein

Question 62

Cholera: (activates/inactivates) G-protein

Answer 62

Activates

Question 63

Pertussis or whooping cough: (activates/inactivates) G-protein

Answer 63

Inactivates

Question 64

In chronic myelogenous leukemia, bcr-abl gene is expressed at (lower/higher) levels.

Answer 64

Higher

Question 65

___ is involved in Alzheimer's disease

Answer 65

Abl kinase