Here's a great AP Biology resource for neurotransmission and action potential. Students are asked to draw a model of pre and postsynaptic membranes with vesicles, ion gated channel proteins, protein receptors, neurotransmitter, synaptic cleft, and mitochondria. They are given a set of eight steps that describe neurotransmission, specifically the chemical synapse. The steps are provided out of sequence so students can arrange them in the correct sequence. This clearly illustrates that this type of communication is a one way process. The AP biology students generally love the ability to draw and color a model and provide their own creative embellishments. This is a great review of terms like action potential, calcium channel, exocytosis, protein receptor, presynaptic and postsynaptic membranes. It's fun and easy to teach!