Question

chemical synapses are characterized by:
a receptors located only on the presynaptic terminal
b the release of neurotransmitter by the presynaptic terminal
c the absence of gap junctions
d the presence of receptors for neurotransmitters on the presynaptic terminal
e connexons that connect the pre - and postsynaptic cells

Explanation:

• Option A: Receptors are on the postsynaptic membrane, not the presynaptic terminal.
• Option B: In chemical synapses, the presynaptic terminal releases neurotransmitters. This is a key characteristic.
• Option C: Gap junctions are present in electrical synapses, not relevant to chemical synapses' main characteristic.
• Option D: Receptors for neurotransmitters are on the postsynaptic terminal.
• Option E: Connexons are part of gap junctions (electrical synapses), not chemical synapses.

Answer:

B. the release of neurotransmitter by the presynaptic terminal