Signal Transduction

Question 1

How do steriods travel in the bloodstream?

Answer 1

Bind to Albumin

Question 2

List pathway of steroids to gene expression

Answer 2

1) steriod binds to receptor in cytoplasm 2) Receptor/Ligand complex =>nucleus 3) Binds to DNA =>gene transcription

Question 3

Autocrine

Answer 3

Same or Identical cell responds to signal

Question 4

Paracrine

Answer 4

single cell secrets ligands that bind only to phenotypically different cells within short distance

Question 5

Endorcrine signaling

Answer 5

Utilizes bloodstream to transport hormones over LONG distances

Question 6

Neuronal signaling

Answer 6

Nerve cell signals to non-neuronal target cell

Question 7

Nitric oxide has what effect on smooth muscle cells

Answer 7

relaxation = dilation of blood vessels

Question 8

Arginine becomes Nitric Oxide after what ligand binds to endothelial cell?

Answer 8

Acetylcholine

Question 9

What is nitroglycerine

Answer 9

Drug that produces Nitric Oxide and causes blood vesells to dilate; relieves angina

Question 10

Kinase proteins can transfer terminal phospate from ATP to OH group of which three amino acids?

Answer 10

Serine Threonine Tyrosine

Question 11

G-Protein coupled receptors are composed of what three subunits?

Answer 11

1) GTPase 2) Beta (B) 3) Gamma (y)

Question 12

How do G-Protein receptors deactivate?

Answer 12

GTPase’s own enzymatic activity turns GTP -> GDP

Question 13

What is the action of Ga-s/GTP

Answer 13

activates enzyme adenylate cyclase

Question 14

What is the action of Ga-i/GTP

Answer 14

inhibits enzyme adenylate cyclase

Question 15

What is the action of Ga-q/GTP

Answer 15

activates enzymes phospholipase C

Question 16

Adenylate cyclase activates what?

Answer 16

Cyclic AMP (cAMP)

Question 17

What is the role of cAMP?

Answer 17

cAMP binds to regulatory subunit of Protein Kinase A which causes the subunit to disassemble -> PKA activated

Question 18

what enzyme deactivates cAMP?

Answer 18

cAMP phosphodiesterase

Question 19

Ga-s are a part of what type of receptors?

Answer 19

B-adrenergic receptors

Question 20

Ga-i are a part of what type of receptors?

Answer 20

a2-adrenergic receptors

Question 21

Ga-q are a part of what type of receptors?

Answer 21

a1-adrenergic receptors

Question 22

When Ga-q binds to GTP, what does it activate?

Answer 22

phospholipase C (PLC)

Question 23

What is the role of Phospholipase C (PLC)?

Answer 23

Cleaves PIP2 forming DAG and IP3

Question 24

what is the role of IP3 in cells?

Answer 24

IP3 binds to endoplasmic reticulum and causes Ca2+ to be released

Question 25

what is the role of CA2+ in a1-adrenergic signaling mechanism?

Answer 25

CA2+ binds to Protein Kinase C and recruits it to DAG and then PKC is fully activated

Question 26

Describe structure of receptor tyrosine kinases (RTK)?

Answer 26

transmembrane proteins that have an extracellular portion that binds to ligand and intracellular portion that is able to phosphorylate itself

Question 27

describe structure of insulin receptor

Answer 27

receptor tyrosine kinase; dimer composed of subunits alpha and beta

Question 28

What key player does insulin receptor activate?

Answer 28

Insulin receptor substate 1 (IRS-1)

Question 29

List process of RTK signaling

Answer 29

1) ligand binds to RTK 2) RTK dimerizes 3) each receptor phosphorylates each other 4) GRB2 binds to receptor 5) SOS binds to GRB2 6) RAS binds to SOS 7) Activated RAS activates MAPK

Question 30

what are the effects of acivated MAPK?

Answer 30

1) cell division 2) altered gene expression 3) cell survival

Question 31

Name a pathway that Insulin Receptor Substrate 1 activates

Answer 31

IRS-1 activates PI3K what activates AKT to increase glucose uptake

Question 32

Does phosphorylation activate or inhibit enzymatic activity?

Answer 32

phosphorylation may activate OR inhibit enzymatic activity

Question 33

What state does insulin favor?

Answer 33

dephosphorylation

Question 34

What state does glucagon favor?

Answer 34

phosphorylation

Question 35

How does glucagon cause phosphorylation

Answer 35

Via Ga-s receptor pathway -\> activates PKA

Question 36

Steriod proteins bind to thier receptors where?

Answer 36

In the cytoplasm

Question 37

Nitric Oxide must perform its signaling function quickly because

Answer 37

It has a short half life

Question 38

Ras is bound to what in its deactivated state?

Answer 38

GDP

Question 39

The ligands Epinephrine and Glucagon act on what type of signaling receptor?

Answer 39

G-protein coupled receptor

Question 40

Nitric Oxide binds to in type of cells

Answer 40

* Guanylyl Cyclase * smooth muscle cells -\> causes relaxation

Question 41

G couple protein receptors (Ga-s; Ga-i; Ga-q) can be stimulated by what common ligand?

Answer 41

Epinephrine