M&R

Question 1

What is hereditary spherocytosis? Pattern of inheritance

Answer 1

Autosomal dominant

Sphere shaped RBCs, more prone to rupture –> anaemia.

Question 2

What is hereditary elliptocytosis? Pattern of inheritance?

Answer 2

Autosomal dominant

elliptical RBCs, prone to rupture – > anaemia. Caused by defect in cytoskeleton meaning the RBCs do not return to their usual shape after leaving microvasculature

Question 3

What cells myelinate peripheral axons and CNS axons?

Answer 3

Peripheral - Schwann

CNS - oligodendrocytes

Question 4

What 3 factors affect conduction velocity?

Answer 4

1. Membrane capacitance - ability to hold charge
2. Membrane resistance - high resistance = high conduction velocity
3. Axon diameter

Question 5

How does an AP at the presynapse result in AP at the post synapse?

Answer 5

1. Calcium comes in
2. Binds to synaptotagmin
3. Results in vesicle brought to membrane and snare complex forming
4. Neurotransmitter release
5. Binds to receptors on post synapse

Question 6

What are the 2 types of blockers of nicotinic receptors?

Answer 6

Depolarising and competitive.

Depolarising blockes - depolarise the membrane over a long period of time and inactivate any nAChRs, preventing new APs.

Question 7

Where is calcium stored in the cell? How can it be released from its stores?

Answer 7

Stored in ER

1. GPCR activated –> IP3 –> IP3 receptors on ER –> Calcium release
2. Calcium induced calcium release - T tubule depolarised –> activated of VOCC –> calcium in subplasmalemmal area –> activates ryanodine receptors in SR membrane.

Question 8

Give the 4 ways a lipid molecule can move in a lipid bilayer

Answer 8

1. Flexion
2. Rotation
3. Diffusion
4. Flip flop

Question 9

How does cholesterol increase membrane fluidity

Answer 9

Reduced phospholipid packing

Stabilises membrane by H bonding

Question 10

What is the RBC cytoskeleton made up of?

Answer 10

Actin and spectrin bound to membrane by ankyrin and glycophorin

Question 11

How does diarrhoea occur?

Answer 11

Phosphorylation of CFTR results in excess loss of Cl- and therefore water

Question 12

Explain phagocytosis, pinocytosis, and receptor mediated endocytosis

Answer 12

phagocytosis - ligand binds to receptor on phagocyte, results in zipper mechanism

Pinocytosis - PM invaginates and internalises molecule

RME - Ligand binds to receptor and recruits clathrin coated pits to internalise it.

Question 13

Explain RME using cholesterol as an example. How does it differ for transferrin containing iron ions and insulin?

Answer 13

1. LDL binds to LDL receptor on surface
2. Clathrin coated pit recruiting and phagosome forms
3. Fuses with endosome, low pH causes dissociated of LDL and receptor.
4. Receptors recycled and endosome fuses with lysosome for digestion

Same for transferrin. With insulin both receptor and insulin degraded.

Question 14

What are the adrenergic and cholinergic receptors linked to: alpha, inhibitory or stimulatory g proteins? What does each g protein do?

Answer 14

Adrenergic Q - alpha 1 - Galpha

                 I - alpha 2 - Ginhib

                S - beta 1 - Gstim

                S - beta 2  - Gstim

Cholinergic Q - M1 - Galpha

                  I - M2 - Ginhib

                 Q - M3 - Galpha

Galpha - +PLC

Ginhib - (-AC)

Gstim - (+AC)

Question 15

What is the kd of a drug?

Answer 15

dissociation constant

concentration at which 50% of the receptors are occupied

Question 16

What is the Emax and EC50 of a drug?

Answer 16

Emax - Conc of drug needed to get 100% response

EC50 - conc of drug needed to get 50% response.

Question 17

What is affinity and efficacy of a ligand?

Answer 17

Affinity - how easily it binds

Efficacy - How good it is at effective a response from the receptor.

Question 18

What is a partial agonist?

Answer 18

a ligand that cannot amount a 100% response

Question 19

What are class 1 and class 2 drugs?

Answer 19

Class 2 drugs - bind to albumin to allow class 1 drugs freedom to act

Class 1 drugs - Object drug

Question 20

What is first order and zero order kinetics? When does each take place?

Answer 20

First order - Fraction of drug eliminated per unit time. Occurs when conc of drug is less than Km

Zero order - Rate of elimination is constant per uni time. Occurs when conc of drug is greater than Km

Question 21

How does pH affect how much drug is excreted?

Answer 21

if drug is acidic and urine acidic reabsorbs more drug and vice versa

Question 22

What enzymes breaks down ACh and NA in cleft?

Answer 22

ACh - acetyl cholinesterase

NA - monoamine oxidase

Question 23

What is tachyphylaxis?

Answer 23

Reduced sensitivity to a drug due to repeated exposure.

Question 24

where are phospholipid made

Answer 24

ER

Question 25

what are integral rbc proteins

Answer 25

Ban 5

glycophorin A

Question 26

give example peripheral RBC proteins

Answer 26

spectrin and actin

Question 27

what is function of ribophoryn

Answer 27

anchors ribosome to RER

Question 28

how can phospholipid move

Answer 28

flex, rotate, lateral diffusion, flip flop

Question 29

actions of cholesterol

Answer 29

increase fluidity by decrease phospholipid packing. decrease fluidity by decrease phospholipid motion. prevents cell state changing

Question 30

how can membrane protein move

Answer 30

rotate, conformational change, lateral diffusion

Question 31

what is amphipathic?

Answer 31

has hydrophobic and hydrophilic regions

Question 32

what are conc of na, k, cl, ca in cell

Answer 32

Na - i10, o150

K - i150, o5

CL- i5, o120

ca - i10(-7), o2

Question 33

how is calcium bound in stores

Answer 33

by calsequeestrin

Question 34

explain how vesicle is released

Answer 34

calcium influx, synaptotagmin binds to vesicle and vesicle then binds to snare complex making a fusion pore

Question 35

what is potency

Answer 35

affinity + efficacy

Question 36

what is pk of drug

Answer 36

half ionisied

Question 37

MoA of Gq

Answer 37

increase PLC which splits PiP2 into DAG and IP3