Cell Signalling

Question 1

Intercellular

Answer 1

Between cells

Question 2

Types of signals

Answer 2

Chemical- majority (short eg neurotransmitter and long range eg hormones)
Physical
Gaseous

Question 3

Chemical intercellular signalling steps

Answer 3

Synthesis and release of the signalling molecule
Transport of signalling molecule to target cell
Detect signal by specific receptor
Change in cellular behaviour triggered by activation of the receptor
Removal of the signal

Question 4

Chemical messenger signal molecules Examples

Answer 4

Insulin, hormones, sugar, peptides, proteins, neurotransmitters

Question 5

What is an agonist

Answer 5

Where are signalling molecule binds and activate a receptor

Question 6

What is an antagonist

Answer 6

A signalling molecule that binds and inactivates receptors

Question 7

Receptors are specific and mostly

Answer 7

Proteins on the cell surface or cytoplasmic

Question 8

Different cells express different

Answer 8

Receptors

Question 9

What causes a quick reaction

Answer 9

Usually ion channels

Question 10

What causes a relatively quick action

Answer 10

G-protein coupled receptors

Question 11

What causes a slow reaction

Answer 11

Kinase linked receptors and nuclear receptors

Question 12

One signalling molecule can activate different

Answer 12

Receptor types

Question 13

Endocrine signalling

Answer 13

Hormones are long-range, they are usually slow chemical communication e.g. insulin, cortisol

Question 14

Paracrine signalling

Answer 14

Short range e.g. nitric oxide

Question 15

Neuronal signalling

Answer 15

Uses neurotransmitters

Question 16

Autocrine signalling

Answer 16

Signalling molecule binds to itselfs receptors

Question 17

Juxtacrine signalling

Answer 17

Contact dependent signalling and uses gap junctions

Question 18

Intracellular signalling

Answer 18

The receptor activation leads to intracellular signalling cascades and second messenger

Question 19

Three stages of intracellular signalling

Answer 19

Reception- CM binds to a protein on CSM
Transduction – binding alters receptors which causes a cascade of reactions
Response – transduction triggers a response e.g. release of enzyme

Question 20

Examples of second messengers

Answer 20

cAMP, InSP3, DAG

Question 21

Signalling molecules are controlled by

Answer 21

Post-translational modification, regulate if a G protein is activated, activators of proteins- The binding changes the confirmation of target proteins which changes the activity

Question 22

Types of receptors

Answer 22

Ligand gated ion channels (iontrophic) , G protein receptors, kinase linked, nuclear receptors

Question 23

Ion channels transport

Answer 23

Sodium, potassium, calcium and chlorine very quickly.

They open due to voltage gated ion channels

Question 24

Ionotrophic receptors open in response to

Answer 24

The binding of a ligand

Question 25

G protein coupled receptors have alpha and

Answer 25

Beta and gamma receptors

Question 26

Alpha receptors activate

Answer 26

An enzyme which causes a cascade of reactions

Question 27

Gamma receptors have an

Answer 27

Alpha receptor attached which is an activated so GDP turns into GTP

Question 28

What do you proteins are activated by agonist

Answer 28

GI, GS, GQ

Question 29

GS

Answer 29

Agonist binds and activate adenyl cyclase which causes an increase in CAMP

Question 30

Gq

Answer 30

Activate phospholipase C which activates IP3 which activates calcium and PKC and then DAG

Question 31

Gi

Answer 31

G I blocks adenyl cyclase so cAMP is not synthesised and there is less cAMP
Inhibitory pathway

Question 32

Enzyme linked receptors Are slower and their stages are

Answer 32

Signalling molecule binds, activates an enzyme e.g. protein tyrosine kinase activity, phosphorylates

Question 33

CytoplasmMatic/nuclear signalling

Answer 33

Alters gene transcription directly