Which statement is true regarding the neuron synapse? • The preganglionic and post ganglionic neurons physically touch Binding of a neurotransmitter on a postganglionic neuron always generates an action potential • Neurotransmitters can be degraded by enzymes within the synaptic cleft to terminate its effect A neural synapse consists of dendrites on a preganglionic neuron and the axon terminal of a postganglionic neuron QUESTION 4 1 points
The Correct Answer and Explanation is:
The correct statement regarding the neuron synapse is:
“Neurotransmitters can be degraded by enzymes within the synaptic cleft to terminate its effect.”
Explanation:
A synapse is the junction between two neurons where communication occurs through the release of neurotransmitters. This is the site where the axon terminal of a presynaptic neuron communicates with the dendrites (or soma) of a postsynaptic neuron.
Now, let’s analyze the statements provided:
- “The preganglionic and postganglionic neurons physically touch”
This is false. In a typical synapse, there is a small gap called the synaptic cleft between the presynaptic and postsynaptic neurons. These neurons do not physically touch each other; instead, the neurotransmitters are released into the cleft and bind to receptors on the postsynaptic membrane. - “Binding of a neurotransmitter on a postganglionic neuron always generates an action potential”
This is also false. When neurotransmitters bind to receptors on a postsynaptic neuron, it may generate a postsynaptic potential (either excitatory or inhibitory), but an action potential is not always generated. Whether an action potential is initiated depends on whether the postsynaptic potential is strong enough to reach the threshold needed for depolarization. - “Neurotransmitters can be degraded by enzymes within the synaptic cleft to terminate its effect”
This is true. Once neurotransmitters are released into the synaptic cleft and have acted on the postsynaptic receptors, they need to be cleared to stop their effect. One of the ways this is done is through enzymatic degradation. For example, the enzyme acetylcholinesterase breaks down acetylcholine in the synaptic cleft, stopping its action on the postsynaptic neuron. - “A neural synapse consists of dendrites on a preganglionic neuron and the axon terminal of a postganglionic neuron”
This is false. The preganglionic neuron refers to a neuron that transmits an impulse to a ganglion, while the postganglionic neuron transmits the signal from the ganglion to the target tissue (such as muscle or gland). In the synapse, the axon terminal of the presynaptic neuron (which could be either preganglionic or postganglionic in different contexts) communicates with the dendrites or soma of the postsynaptic neuron, not the other way around.
In summary, the termination of the neurotransmitter’s action by enzymatic degradation is a crucial part of regulating synaptic communication, and this statement is the correct one among the options.
