Cell Signaling by Chemical Messengers

Question 1

Cell signaling vs. signal transduction

Answer 1

Signaling - between cells

Signal Transduction - extracellular signal converted to intracellular response

Question 2

Cell signaling steps

Answer 2

Chemical messenger secreted by cell bc of stimulus
Messenger diffuses and transported to target cell
Specific receptor binds messenger
Binding elicits response
Termination

Question 3

Specifity of receptor dictated by

Answer 3

Type of receptor and location

Question 4

Most receptors bind

Answer 4

A single messenger type

Question 5

Endocrine signaling

Answer 5

Cell sending out signal is pretty far away…usually transported through blood

Question 6

Paracrine signlaign

Answer 6

Signaling cell is close

Question 7

Autocrine signaling

Answer 7

Cell signals to itself

Question 8

Nervous system messenging molecules and type

Answer 8

Small molecule neurotransmitters and neuropeptides

Paracrine

Question 9

Endocrine system molecules and type

Answer 9

Endocrine

Endocrine hormones

Question 10

Glucagon is ______ system and does what

Answer 10

Response to low glucose levels
Glycogenolysis
Endocrine

Question 11

Immune system molecules and type

Answer 11

Cytokines

Auto, para, and endo

Question 12

Eicosanoids molecules and types

Answer 12

Derived from arachidonic acid
Control response to injury
Para and auto

Question 13

Growth factors molecules and type

Answer 13

Proliferation, differentiation, and apoptosis

Paracrine

Question 14

4 receptor types from fast to slow

Answer 14

Channel-linked receptors (ionotropic)
GPCR (metabotropic)
Kinase-linked
Nuclear receptors (linked to gene transcription)

Question 15

What can nuclear receptors bind?

Answer 15

Things that can get through membrane into the nucleus

Question 16

Channel-linked receptors also known as

Answer 16

Gated ion channels

Question 17

Agonist

Answer 17

Messenger that opens an ion channel

Question 18

Example of Gated ion channel

Answer 18

Nicotinic acetylcholine receptor

Question 19

Nicotinic acetylcholine receptor…what does it do, where is it found

Answer 19

Neuromuscular junctions - muscle contractions

Sense Ach and lets Na in and K out of muscle fiber

Question 20

Nicotinic acetylcholine mechanism

Answer 20

AP in motor neruon
V gated ion channel lets Ca into cell
Vesicle of Ach fuses at post synaptic membrane
Ach diffuses and binds nicotinic acytylcholine receptor
Propogates signal through muscle fiber

Question 21

How is acetylcholine receptor mechanism turned off?

Answer 21

Acetylcholinesterase degrades Ach

Question 22

Myasthenia Gravis is what kind of disorder?

Answer 22

Acquired autoimmune

Question 23

MG pathology

Answer 23

Produce antibodies to nicotinic Ach receptor…antibodies bind and cross-link receptor…complex andocytosed and degraded by lysosome…patient has fewer neuromuscular junctions and therefore lots of muscle fatigue

Question 24

MG symptoms

Answer 24

Difficulty walking
Difficulty extending arms
Drooping eyelids

Question 25

Tyrosine kinase receptors mechanism

Answer 25

Signal dimer binds Kinase activity stimulated in the cytosol Tyrosines phosphorylated Intracellular proetins bind to phospho-tyrosine binding site

Question 26

Tyrosine kinase receptors form _____ dimers

Answer 26

Homo

Question 27

Tyrosine kinase external/internal domains

Answer 27

External - receptor | Internal - tyrosine kinase

Question 28

Ras mutations

Answer 28

Mutations that turn Ras on will cause cancer

Question 29

Ras causes

Answer 29

Proliferation, survival, and growth

Question 30

Ras pathway

Answer 30

EGF binds EGFR (receptor tyrosine kinase)...recruits GRB2...Recruits SOS...Recruits Ras...Ras phosphorylates Raf...phosphorylates...MEK...Phosphorylates Erk...acts on DNA

Question 31

Serine/threonine kinase messengers

Answer 31

TGF beta and Bone morphogenic factors

Question 32

Serine/threonine kinase signal

Answer 32

Smad proteins

Question 33

Serine/threonine kinase forms _____dimer

Answer 33

Hetero

Question 34

Nuclear receptors are

Answer 34

Intracellular proteins with extracellular messengers

Question 35

Messengers of nuclear receptors are typicall _____ and example

Answer 35

Hydrophobic | Steroids

Question 36

2 types of steroid hormones

Answer 36

Cytoplasm (glucocorticoid) | Nucleus (more common)

Question 37

Glucocorticoids include

Answer 37

Cortisol, corticosterone, and aldosterone

Question 38

Cortisol regulates

Answer 38

Cardiovascular, metabolic, and immuno functions

Question 39

Glucocorticoid pathway

Answer 39

Glucocorticoid binds receptor that has chaperone proteins attached...chaperones leave...GR dimerizes and binds to DNA causing changes

Question 40

Cortisol released from ___ in response to ____

Answer 40

adrenal cortex | Chronic stress

Question 41

Cortisol acts n various tissues to do what in acute stress?

Answer 41

Change enzyme levels and redistribute nutrients

Question 42

Cortisol and liver

Answer 42

Can upregulate liver proteins in gluconeogenesis to provide rapid response to hypoglycemia

Question 43

PPAR receptor messenger and response

Answer 43

Fatty acids and derivatives | Regulate transcription of genes

Question 44

PPAR pathway

Answer 44

Bind PPAR...PPAR dimerizes with RXR...binds to DNA to function

Question 45

Gap junction other names

Answer 45

Nexus | Macula communicans

Question 46

Gap junctions connect

Answer 46

Cytoplasm of 2 cells

Question 47

Gap junctions allow passage of

Answer 47

Molecules and electrical impulses

Question 48

Gap junctions not found in

Answer 48

Skeletal muscle or mobile cell types

Question 49

Gap junction consists of two

Answer 49

Connexons (hemichannels) one on each cell

Question 50

Eahc connexon is

Answer 50

Homo/hetero hexamer of connexin proteins

Question 51

Gap junction size exclusion

Answer 51

500 Da

Question 52

Gap junctions are especailly important in

Answer 52

Heart