1st semester: Second messenger

Question 1

Protein kinase C is

Answer 1

DAG dependent protein kinase

Question 2

In cell signaling, the receptor need to have the ff.:

Answer 2

High affinity
Exhibit Specificity
Saturation

Question 3

What happens when there is prolonged exposure of a receptor to a ligand?

Answer 3

It undergoes down regulation

Question 4

Paracrine signaling is involved in which of the following?

Answer 4

chemical signals that can only travel limited distances between cells

Question 5

activation of G protein happen when ______

Answer 5

alpha-subunit dissociates A-gamma subunit

Question 6

physiologic event that immediately happens when ANP binds to a receptor guanylyl cyclase

Answer 6

Conformational change of receptor resulting to its DIMERTIZATION

Question 7

Tyrosine-Kinase receptors

Answer 7

activates signaling pathways that result in protein phosphorylation reactions upon binding of their specific ligands

Question 8

Catalyzes the cutting of PIP2 into 2 moles of IP3 and diacylglycerol in cell signaling

Answer 8

Phospholipase C

Question 9

The ff. are involved in signal transduction by Beta-adrenergic receptor pathway

Answer 9

ATP
PKA
cAMP

Question 10

A hormone/ligand can be considered as

Answer 10

FIRST MESSENGER

Question 11

The binding of ligands to many GPCRs leads to

Answer 11

INCREASE in concentration of certain extracellular signal molecules [1st msgrs]

Question 12

It has an antagonistic action to ADENYLYL CYCLASE

Answer 12

phosphodiesterase (PDE)

Question 13

MONOMERIC G protein GTPase that regulate cell division and differentiation

Answer 13

Ras

Question 14

TRUE about G protein

Answer 14

They bind to and are regulated by ADENINE NUCLEOTIDES
They must be active before the cell can synthesize needed cAMP
Involved in signal cascades

Question 15

Inactivation of the cellular response can be brought about by

Answer 15

ENDOCYTOSIS of the signal molecule-receptor complex
Enzymatic degradation of the NTs in the synaptic cleft
Cessation of the release of the ligand

Question 16

effector proteins is stimulated when a ligand activates a receptor that is coupled to a G protein with an alpha-s subunit

Answer 16

ADENYLYL CYLASE

Question 17

Activation of lipoxygenase enzyme will result to the release of ______ from ARACHIDONIC ACID

Answer 17

Leukotrienes

Question 18

This event will occur if a ligand binds with metabotropic receptors on a target cell

Answer 18

generation of 2nd messengers

Question 19

a G-protein is active when ______

Answer 19

GTP is bound to its alpha-subunit

Question 20

events observed in G protein coupled receptor activation

Answer 20

alpha-q -> (+) phospholipase C -> increased DAG -> protein kinase C
alpha-s -> (+) adenylyl cyclase -> increased cAMP -> PKA
alpha-i -> (-) adenylyl cyclase -> decreased cAMP -> (-) PKA