In experiment 1, instead of an electric pulse, you inject the presynaptic cell w
ID: 262779 • Letter: I
Question
In experiment 1, instead of an electric pulse, you inject the presynaptic cell with Ca2+ and see that it causes an action potential in the postsynaptic cell. Which of following conclusions about experiment 1 is supported by the data?
Question 7 options:
a)
b)
c)
d)
e)
In experiment 2, you monitor presynaptic cells that have been injected with the chemical BAPTA. This chemical doesn't affect the membrane potential of the cell. Based on the results of experiment 2, what is the likely mechanism of BAPTA activity?
Question 15 options:
a)
b)
c)
d)
e)
a)
The Ca2+ ions in the presynaptic cell depolarize the membrane, which causes neurotransmitter release.b)
The Ca2+ ions in the presynaptic cell cause the release of neurotransmitter, which cause the opening of ion channels on the postsynaptic cell.c)
None of the answers are supported by the data.d)
The postsynaptic cell fires an action potential without binding to neurotransmitter because of the Ca2+ ions.e)
The Ca2+ ions are traveling from the presynaptic cell to the postsynaptic cell. Experiment 1 Ca2+ injected into presynaptic cell BAPTA injected into presynaptic cell before electric pulse CONTROL 25 No electric pulse 25 S-50 E -75 You perform an Electric pulse Electric pulse E 25 Untreated -25 -50 0 1 2 3 40 1 2 3 40 1 2 3 4 experiment to better understand synaptic transmission. You monitor the membrane potential of the presynaptic and postsynaptic cell, and those data are displayed. You stimulate the presynaptic cell with an electric pulse and see that it causes an action potential in the postsynaptic cell, as indicated in the control experiment Reference: synapsisExplanation / Answer
7) Option 'b' is the correct answer.
In the presynaptic neurons, the influx of calcium ions triggers the fusion of the neurotransmitter?filled synaptic vesicles with the cell membrane, thereby releasing their contents into the synaptic cleft which causes opening of the ion channels on the postsynaptic cells, thereby causing transmission of nerve impulse across the synapse.
8) Option 'e' is the correct answer.
BAPTA is a selective, membrane-permeable calcium chelator. It has a high affinity for calcium. It is widely used as an intracellular calcium sponge. Introducing BAPTA in experiment 2 will lead to binding of calcium ions to BAPTA, thereby putting a stop to the neurotransmitter release across the synaptic cleft for the firing of postsynaptic neuron.