The chemical causing the transmission of nerve impulse across synapses is

Explain:
$(1)$ Electrical Synapse
$(2)$ Chemical Synapse

Explain the process of transport and release of neurotransmitter with the help of a labelled diagram,showing complete neuron,axon terminal and synapse.

What is responsible for the unidirectional transmission of nerve impulses in a neuron?

Which of the following statements is correct regarding electrical synapses?
$I.$ Pre and postsynaptic membranes are in very close proximity at electrical synapses.
$II.$ Electric currents are involved in the transmission of impulses.
$III.$ Transmission of an impulse across electrical synapses is very similar to impulse conduction along a single axon.
$IV.$ Impulse transmission is always faster in electrical synapses than across chemical synapses.
$V.$ Electrical synapses are rare in our system.
The correct option is:

What does the enzyme acetylcholinesterase break down acetylcholine into?