Question

The specific receptors for neurotransmitters in a synapse are present on ________.

• A. Post-synaptic membrane
• B. Pre-synaptic membrane
• C. Myelin sheath
• D. Schwann cell

Hint:

Logic Tip: Communication is a one-way street at a chemical synapse. The "Pre-" side speaks (releases neurotransmitters), and the "Post-" side listens (has the receptors).

Answer 1

The Correct Option is A

Concept:
A chemical synapse consists of a pre-synaptic neuron that releases a chemical signal, a synaptic cleft (the gap), and a post-synaptic neuron that receives the signal. The transmission of a nerve impulse relies on the highly specific interaction between neurotransmitters and their target receptors.
Step 1:
When an action potential arrives at the axon terminal of the pre-synaptic neuron, it triggers synaptic vesicles to fuse with the pre-synaptic membrane and release neurotransmitters into the synaptic cleft.
Step 2:
The released neurotransmitter molecules rapidly diffuse across the fluid-filled synaptic cleft to reach the target cell on the other side.
Step 3:
To successfully pass the signal, the neurotransmitters must bind to specific receptor proteins. These receptors are localized entirely on the surface of the post-synaptic membrane.
Step 4:
The pre-synaptic membrane (Option 2) releases the transmitter, it does not primarily receive it to continue the main impulse. The Myelin sheath (Option 3) and Schwann cells (Option 4) are involved in insulating the axon to speed up conduction, completely unrelated to chemical synaptic transmission at the axon terminals.
Step 5:
Thus, the specific receptors are located on the post-synaptic membrane.