synapses

Question 1

what are snare proteins?

Answer 1

soluble NSF attachment protein receptor:

synaptobrevin/ VAMP( vesicle associated membrane protein)
as a vesicular protein synaptobrevin is a V-SNARE

syntaxin: location is on target membrane : T-SNARE

SNAP-25: also a t-snare, located on cytoplasmic face of plasma membrane

Question 2

how do snare proteins mediate vesicle exocytosis at synapses?

Answer 2

once vesicle is within vicinity of presynaptic plasma membrane the cytoplasmic domains of synaptobrevin, syntaxin and SNAP-25 form a tight complex, the force generated by assembly of complex brings vesicle to membrane and leads lipid bilayers to fuse so synaptic contents are exposed to extracellular space

Question 3

how is the NMDA receptor a coincidence receptor?

Answer 3

detects presence of glutamate release and postsynaptic depolarisation

Question 4

what are 3 types of ionotropic glutamate receptors?

Answer 4

AMPA and kainate receptors which allow flow of monovalent cations ( some AMPARs allow small degree of calcium flow)

NMDA receptors which allow calcium and monovalent cations (agonist is glutamate and glycine)

Question 5

how much depolarisation (in voltage) will a current cause?

Answer 5

V=IR

if given current and resistance of axon it can be determined