A list of events occurring in the transmission of nerve impulse across the synapse is given below in a random order
(i)Opening of specific ion channels allows the entry of ions, a new action potential is generated in the post-synaptic neuron.
(ii)Neurotransmitter binds to the receptor on post synaptic membrane.
(iii)Synaptic vesicle fuses with pre-synaptic membrane, neurotransmitter release into synaptic cleft.
(iv)Depolarisation of pre-synaptic membrane.
(v)Arrival of action potential at axon terminal.
Which of the following options represents these events in a correct order ?

Options

A. `(v)to(iv)to(iii)to(ii)to(i)`
B. `(i)to(ii)to(iii)to(iv)to(v)`
C. `(i)to(ii)to(iv)to(iii)to(v)`
D. `(v)to(iv)to(iii)to(i)to(ii)`

Explanation

To determine the correct order of events occurring in the transmission of a nerve impulse across the synapse, we can analyze the provided steps one by one. Here’s the step-by-step solution:

1. **Arrival of Action Potential at Axon Terminal (Step v)**: The process begins when an action potential travels down the axon and reaches the axon terminal of the presynaptic neuron. This is the initial trigger for the subsequent events.

2. **Depolarization of Pre-synaptic Membrane (Step iv)**: The arrival of the action potential causes depolarization of the presynaptic membrane. This change in membrane potential is crucial for the next steps.

3. **Synaptic Vesicle Fuses with Pre-synaptic Membrane (Step iii)**: Following depolarization, synaptic vesicles containing neurotransmitters move toward the presynaptic membrane and fuse with it. This fusion is essential for the release of neurotransmitters into the synaptic cleft.

4. **Neurotransmitter Binds to the Receptor on Post-synaptic Membrane (Step ii)**: Once released, the neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the postsynaptic membrane. This binding is necessary for the next step.

5. **Opening of Specific Ion Channels Allows the Entry of Ions (Step i)**: The binding of neurotransmitters to their receptors leads to the opening of ion channels in the postsynaptic neuron. This allows ions (such as sodium) to enter the neuron, resulting in depolarization and the generation of a new action potential in the postsynaptic neuron.

Thus, the correct order of events is:
v → iv → iii → ii → i