Which of the Following Structures is Not Part of a Synapse

Question

Which of the following structures is not part of a synapse?
A) synaptic knob
B) synaptic cleft
C) neurotransmitter
D) plasma membrane of the postsynaptic cell

Accepted Answer

The neurotransmitter is not part of a synapse. It is a chemical that is released by the presynaptic neuron and travels across the synaptic cleft to bind to receptors on the postsynaptic neuron's plasma membrane. The structures that are part of a synapse include the synaptic knob (terminal button) of the presynaptic neuron, the synaptic cleft (the gap between the pre- and postsynaptic neurons), and the plasma membrane of the postsynaptic neuron.