CAIE A-Level Biology A2 15.1.9 Cholinergic Synapse Structure and Function Questions

1 A voltage-gated and B ligand-gated / not voltage-gated or
A opens in response to, depolarisation / arrival of an action potential and
B opens in response to binding of, acetylcholine / neurotransmitter ;
2 A for calcium ions and B for sodium ions ;

any four from:
1 no $\mathrm{Ca}^{2+}$ enter (presynaptic, knob / neurone) ;
2 vesicles do not, move towards / fuse with, presynaptic membrane ;
3 no, ACh / neurotransmitter, released
or
no exocytosis of, ACh / neurotransmitter ;
4 ACh / neurotransmitter, does not bind to, receptor / ion channel B ;
$5 \mathrm{Na}^{+}$does not enter postsynaptic neurone / ion channel B does not open ;
6 postsynaptic membrane not depolarised
or
no action potential generated
or
impulse not transmitted ;

any two from:

1 inside more negative (charge)
or
membrane hyperpolarised / membrane potential decreases / potential difference increases ;

2 harder to / cannot, reach threshold ;

3 no depolarisation of membrane / harder to depolarise membrane
or
no
/ fewer / harder to generate, action potentials / impulses ;
2

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