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Flashcards in ICPP Deck (119)
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1

Name an amine hormone

NA, adrenaline, dopamine, 5-HT

2

Out of amine, peptide and steroid hormones, order how long their half lives are

Amine seconds, peptide minutes, steroids hours

3

Name an amino acid neuroT

Glutamate, glycine, GABA

4

What are metabotropic receptors?

GPCRs

5

How do ionotropic Rs carry out their effects?

Ca2+ coupled

6

Name the alpha protein and effector molecules involved in GPCRs

a1 Gaq activ PLC --> IP3 and DAG
a2 Gai inhib AC --> cAMP --> PKA
B Gas activ AC --> cAMP --> PKA
M1/3 Gaq activ PLC --> IP3 and DAG
M2/4 Gai inhib AC --> cAMP --> PKA

7

Describe the structure of a GPCR

7TM, single polypeptide, N terminus is extracellular and C terminus intracellular

8

What happens following PLC activation

Has two effectors, IP3 and DAG. IP3 joins to IP3 receptor on SR/ER which causes calcium release. DAG activates PKC which phosphorylates proteins

9

What happens following AC activation

AC hydrolyses ATP to create cyclic AMP which then activates PKA which phosphorylates proteins

10

At what stage is there signal amplification in GPCR signalling

AC activates many molecules of cAMP
PKA phosphorylates many proteins
PLC activates two effectors (IP3 and DAG)
DAG phosphorylates many proteins

11

Name all the calcium transporters/channels in a cell

Plasma membrane: NCX, PMCA Ca out, NOCC Ca in, LGIC Ca in
SR/ER: IP3 Ca out, SERCA Ca in, CICR (ryanodine Rs) Ca out

12

Which molecules can pass through the lipid bilayer?

Small uncharged polar or any hydrophobic molecules

13

What determines rate of passive transport?

Permeability coefficient and concentration gradients on each side J=P(C1-C2)

14

If ∆G is positive, what does this mean about the transport process?

Its active transport! ∆G negative is passive transport

15

What determines if it will be active or passive transport?

Dependent on concentration ratio and membrane potential

16

What are the glucose and fructose transporters for both sides?

Glucose SGLT, fructose GLUT5 and then both GLUT2 on basolateral side

17

Give an example of an ATPase Calcium transporter

PMCA (transports Ca out of cell)

18

What type of transporter is SGLT?

Cotransporter/symtransporter. Transports Na and glucose into cell

19

What is mainly responsible for RMP of -70mV?

Passive K+ diffusion out of cell through K+ channels
NOT Na/KATPase, this is only responsible for 5-10mV

20

Name two antiports

NCX (NaCa), NHE (Na H)

21

How does NaKATPase drive secondary active transport?

Drives Na out so provides energy for transporters that bring Na in e.g. Na/H or Na/Ca antiports or Na/glucose Na/aa symport

22

Name primary active, secondary active and facilitated transporters in Calcium

Primary active: PMCA (Na/CaATPase), SERCA
Secondary active: NCX
Facilitated: mitochondrial Ca uniports at high Ca to buffer harmful effects

23

What is NCX?

3 Na in, one Ca out (can reverse mode of operation if low Ca or high Na

24

Why do you get reversal of NCX activity in ischemia?

So normally NCX moves 3Na in and 1Ca out, but if ischaemic then NaCaATPase (PMCA) doesn't work so then Na accumulates in cell so NCX reverses direction

25

What transporters control cell pH

NHE (Na in H out antiport), AE (HCO3- out, Cl- in)

26

What do you need to have a membrane potential?

Ion gradients and selective ion channels

27

What is the nernst equation?

Gives the equilibrium potential for an ion (=where chemical and electrical charges are balance) i.e. the membrane potential where the ion will be in equilibrium

28

If you increase membrane permeability, you move it closer/further away from its equilibrium potential?

Closer to its equilibrium potential

29

What is fast synaptic transmission?

Where the R is also an ion channel e.g. Nictonic ACh R that lets sodium in

30

What are excitatory and inhibitory synapses?

Ligand-gated ion channels
Excitatory causes EPSP (ACh, glutamate, dopamine) and inhibitory cause IPSP (glycine, GABA)