Select the correct statement regarding chemical synapses.
A) the synaptic cleft uses the action potential to release a chemical signal to the post synaptic cell
B) neurotransmitter receptors are located on the pre-synaptic axon terminals
C) the release of neurotransmitter molecules give cells the property of being electrically coupled
The Correct Answer and Explanation is:
The correct answer is A) the synaptic cleft uses the action potential to release a chemical signal to the postsynaptic cell.
Explanation:
Chemical synapses are specialized junctions that allow neurons to communicate with one another or with other types of cells (like muscle or gland cells). They differ from electrical synapses in that they use chemical signals, rather than electrical signals, to transmit information.
Here’s a breakdown of the options:
- Option A: “The synaptic cleft uses the action potential to release a chemical signal to the postsynaptic cell” is correct. The synaptic cleft is the small gap between the presynaptic and postsynaptic cells. When an action potential travels along the presynaptic neuron to its axon terminal, it causes the release of neurotransmitters into the synaptic cleft. These neurotransmitters cross the cleft and bind to receptors on the postsynaptic cell, transmitting the signal. This is a key feature of chemical synapses, where the action potential triggers the release of chemical signals (neurotransmitters) that influence the postsynaptic cell.
- Option B: “Neurotransmitter receptors are located on the presynaptic axon terminals” is incorrect. Neurotransmitter receptors are located on the postsynaptic membrane (on the receiving cell), not on the presynaptic axon terminal. The presynaptic terminal contains vesicles filled with neurotransmitters, which are released when an action potential reaches the terminal.
- Option C: “The release of neurotransmitter molecules gives cells the property of being electrically coupled” is also incorrect. Electrical coupling refers to electrical synapses, where ion channels (gap junctions) directly connect adjacent cells, allowing for the passage of ions and the spread of electrical signals. In chemical synapses, there is no direct electrical coupling; instead, neurotransmitters are released and bind to receptors to trigger electrical responses in the postsynaptic cell.
Thus, the correct answer is A, as it accurately describes the process of neurotransmitter release and signal transmission across a synaptic cleft in a chemical synapse.