Signal Transduction

Question 1

What does. Ligand binding to a receptor cause?

Answer 1

Conformational change in the protein receptor

Question 2

Apart from being embedded in the cell membrane, where can receptors be found?

Answer 2

Nucleus or cytoplasm

Question 3

When the agonist binds to the receptor, what does this allow? (Pathway)

Answer 3

Confo change and the receptor can activate the effector ligand and cause a signal transduction

Question 4

Are signal transduction pathways conserved in the body?

Answer 4

Yes

Question 5

What are the 4 major signal transduction pathways?

Answer 5

Ion channel

GPCR

Tyrosine kinase linked receptors

Nuclear/intracellular receptors

Question 6

What type of signalling molecule activate the nuclear receptors?

Answer 6

Lipophillic

Question 7

What are the 2 types of ion channels?

Answer 7

Ligand gated

Voltage gated

Question 8

What is an example of a ligand gated channel?

Answer 8

GABA

Question 9

Where does benzodiazapine bind on the GABAa receptor?

Answer 9

Binds to an allosteric binding site, effect the affinity of binding for GABA molecules, more likely to. Ind, channel more likely to open and. Abuse influx of chloride into the cell

Question 10

How does the BDZ cause sedation?

Answer 10

Causes a negative intracellular charge, making it harder for an ap to occur and therefore causes sedation

Question 11

Does BDZ cause the gaba channel to open for longer or more frequently?

Answer 11

More frequently

Question 12

Do barbiturates cause the gaba channel to open for longer or more frequently?

Answer 12

Open for longer

Question 13

What is the normal charge of the intracellular cytoplasm?

Answer 13

Negative

Question 14

What is the only way for ions to cross the cell membrane?

Answer 14

Ion channels

Only way cells can redistribute charge

Question 15

What charge if molecule causes the firing of an AP?

Answer 15

Sodium

Depolarise cell

Question 16

What is the Kemal charge if a cell at rest?

Answer 16

-70mV

Question 17

Why does the cell becoming less negative make it easier to stimulate an AP?

Answer 17

Less negative, so need less additional positive charge to cause a stimulus

Question 18

Does benzodiazapine bind to the same or different from ligand?

Answer 18

Different

Question 19

What channels does LA inhibit?

Answer 19

Voltage gated sodium channels

Question 20

What part of LA blocks the sodium channel?

Answer 20

The amide side chain

Question 21

What 2 firms can LA exist?

Answer 21

Non-iodised and iodised

Question 22

From where do LA block sodium channels?

Answer 22

Penetrates the cell membrane in the non iodised form (pass through cell), blocks channel in the iodised form from the inside (extra hydrogen)

Question 23

What forms can LA pass the membrane and block the channel?

Answer 23

Question 24

What does the balance of LA iodised and non-iodised depend on?

Answer 24

PH

Question 25

What pH drives the LA to the left?

Answer 25

To the left, more ionised state

Question 26

Why is LA less effective in inflamed tissue?

Answer 26

PH is lower (more acidic)

The La will take on the ionised form and cannot pass through the membrane

Question 27

What neurones is LA more effective in?

Answer 27

Small, rapidly firing neurons (e.g. pain fibres)

Question 28

Does LA show dependence?

Answer 28

Yes, the more the AP is fired the less effective it becomes, we’d more LA