Beginning at the synapse of a neuron, place the events in neuronal signaling in the correct sequence.1. Ion channels bind the ligand and open.2. Na+ is pumped out of the cell, and the membrane potential is restored.3. Acetylcholinesterase breaks down acetylcholine.4. Na+ enters the postsynaptic cell, and the membrane potential changes.5. Acetylcholine is released into the synapse.6. Na+ ion channels close. A. 3, 4, 6, 1, 5, 2B. 5, 1, 4, 3, 6, 2C. 4, 5, 1, 2, 6, 3D. 1, 2, 3, 4, 5, 6E. 6, 4, 3, 1, 2, 5

B. 5, 1, 4, 3, 6, 2

Explanation:

Acetylcholine (ACh) is a molecule that functions as a neurotransmitter and plays diverse roles in brain and muscle function. Ach is released by the presynaptic neurons into the synaptic cleft. The nicotinic acetylcholine receptors are ACh ligand-gated ion channels located at the postsynaptic membrane which admit both sodium (Na+) and potassium (K+) ions. These receptors bind ACh, increasing the permeability of the postsynaptic membrane to Na+ and K+ ions. In consequence, ion channels open and sodium (Na+) ions enter the postsynaptic cell, causing the postsynaptic membrane to depolarize. An enzyme known as acetylcholinesterase breaks down acetylcholine into acetate and choline. If depolarization passes a threshold potential, an action potential is generated in the postsynaptic membrane. The generation of a postsynaptic potential at the excitatory synapse is known as excitatory postsynaptic potential. Once depolarization is complete, Na+ channels close and membrane permeability to Na+ ions declines to the resting levels.