Membranes and Receptors

Question 0

3 types of protein mobility.

Answer 0

Conformational change
Rotational
Lateral

Question 1

4 types of phospholipid motion.

Answer 1

Flexion/Conformation
Rotation
Lateral Diffusion
Flip Flop

Question 2

Restraints of protein mobility

Answer 2

Separate to fluid/cholesterol poor region
Association between proteins in membrane
Peripheral protein association (Aggregation, Tethering, Interaction with cells)

Question 3

What is Black Film?

Answer 3

A container with a divide containing a small section of lipid bilayer.

Question 4

Difference in Passive and Active transport in terms of ΔG.

Answer 4

Passive has -ΔG

Active has +ΔG

Question 5

Define co transport.

Answer 5

1< type of ion or molecule transported on membrane transporter.

Question 6

Define antiport.

Answer 6

2 or more ions transported in opposite directions across membrane.

Question 7

Define Symport.

Answer 7

2 or more ions/molecules transported in same direction across membrane.

Question 8

Average Na concentrations.

Answer 8

Extra = 145 mM
Intra = 12mM

Question 9

Average K concentration

Answer 9

Extra 4 mM

Intra 155 mM

Question 10

Average Ca concentration.

Answer 10

Extra 1.5 mM

Intra 0.1μM

Question 11

Average Cl concentration

Answer 11

Extra 123 mM

Intra 4.2 mM

Question 12

Define membrane potential

Answer 12

Potential difference across a membrane in a cell

Question 13

What is Nernst equation used for?

Answer 13

Finding Equilibrium Potential

Question 14

What is conductance (g)?

Answer 14

Increases by increase in number of channels for that ion.

Increase in g moves membrane potential (Vm) toward equilibrium potential for that ion.

Question 15

What is a voltage clamp?

Answer 15

Prevents change in membrane voltage in response to membrane current.

Question 16

Define ARP

Answer 16

Absolute Refractory Period

All Na channels inactivated

Question 17

Define RRP

Answer 17

Recovery of Na channels from inactivation.

Excitability returns to normal.

Question 18

Give an example of a Complete Blocker of nAChR

Answer 18

Tubocurarine

Question 19

Give an example of a Depolarisation Blocker of nAChR

Answer 19

Succinylcholine

Question 20

What is capacitance in terms of current?

Answer 20

Ability to store charge

Question 21

How is conductance calculated?

Answer 21

1/Resistance

Question 22

Define paracrine cell signalling

Answer 22

Signalling between cells via local mediator

Question 23

Define endocrine cell signalling

Answer 23

Signalling via hormone in the blood

Question 24

Define synaptic signalling

Answer 24

Signalling by neurotransmitter

Question 25

Define receptor

Answer 25

Molecule that recognises a specific ligand or family of ligands and which brings about regulation of a cellular process

Question 26

Define ligand

Answer 26

Molecule which binds specifically to a receptor site

Question 27

What is the difference between agonist and antagonist?

Answer 27

Agonist activates receptor | Antagonist combines with receptor but with no activation

Question 28

Define phagocytosis

Answer 28

Internalisation of particulate matter.

Question 29

Define pinocytosis

Answer 29

Invagination of membrane to produce a vesicle

Question 30

Define endocytosis

Answer 30

Selective internalisation by specific cell surface receptors

Question 31

3 principles of signal transduction.

Answer 31

Diversity Specificity Amplification

Question 32

Define affinity

Answer 32

Ability of ligand to bind to target receptor

Question 33

Define intrinsic efficacy

Answer 33

Ability of ligand to activate cellular response

Question 34

Define Bmax

Answer 34

Maximum binding capacity (receptor number)

Question 35

Define Kd

Answer 35

Concentration of ligand needed for 50% receptor occupancy.

Question 36

Define EC50

Answer 36

Effective concentration needed to give 50% maximal response.

Question 37

Define Emax

Answer 37

Maximum cellular response

Question 38

What is potency?

Answer 38

Combination of both affinity, intrinsic efficacy and efficacy.

Question 39

What is the difference between intrinsic efficacy and efficacy?

Answer 39

Intrinsic efficacy is how well the ligand activates the receptor. Efficacy is how well the activated receptor generates a cellular response.

Question 40

What is meant by spare receptors?

Answer 40

EC50

Question 41

How do spare receptors affect potency?

Answer 41

Increased sensitivity at low concentrations therefore increased potency. Allows for variation in sensitivity.

Question 42

Define IC50

Answer 42

Concentration of antagonist giving 50% inhibition.

Question 43

What is KB?

Answer 43

Kd when antagonist is derived pharmacologically.

Question 44

Define pharmacokinetics

Answer 44

What the body does to the drug.

Question 45

Define oral bioavailability

Answer 45

Proportion of dose given orally that reaches systemic circulation unchanged.

Question 46

How is bioavailability expressed?

Answer 46

Amount or Rate

Question 47

Explain how bioavailability is measured by amount

Answer 47

Area under curve of blood drug level vs time.

Question 48

How is bioavailability measured by rate?

Answer 48

Measured by peak height and rate of rise of drug level in blood.

Question 49

What is the therapeutic ratio?

Answer 49

Maximum Tolerated Dose/Minimum Effective Dose

Question 50

How is therapeutic ratio calculated?

Answer 50

Lethal Dose 50% of people/Effective Dose 50% of people

Question 51

Define first pass metabolism

Answer 51

Occurs when drug absorbed in ileum and enters venous system. Through hepatic portal vein to liver. Extensively metabolised here.

Question 52

How can first pass effect be avoided?

Answer 52

Parenteral, Sublingual or Rectal administration.

Question 53

Define drug distribution

Answer 53

Theoretical volume that a drug is distributed into assuming this is instantaneous.

Question 54

How is dug distribution calculated?

Answer 54

Amount given/Plasma Concentration at Time 0

Question 55

Define Class 1 drug

Answer 55

Dose < number of albumin binding sites

Question 56

Define Class II drug

Answer 56

Dose is greater than number of albumin binding sites

Question 57

What is first order kinetics?

Answer 57

Metabolism is proportional to drug concentration

Question 58

What is the calculation for first order rate of metabolism?

Answer 58

Rate = Vmax x [C]/Km

Question 59

What is zero order kinetics?

Answer 59

Rate of metabolism is constant

Question 60

After how many half lives is the steady state reached?

Answer 60

5