Answer:E) Voltage-gated calcium channels open
F) Calcium enters the synaptic knob
G) Synaptic vesicles merge with synaptic knob plasma membrane
H) Neurotransmitter is released by exocytosis
B) Neurotransmitter attaches to receptors on a muscle, neuron, or gland cell
I) Action potential reaches synaptic knob
Explanation:
Transport proteins multi-pass so that multiple alpha helices can form a hydrophilic pore that is able to diffuse small molecules. If transport proteins were single-passing, the alpha helix would not have a core with a diameter large enough to diffuse solutes.
Multi-pass membrane proteins loop in and out, while single-pass membrane proteins cross the membrane once.
Answer: "B" epididmysis
Explanation: The epididmysis are coiled tubes that are right behind the testicles. These coiled tubes lie above the testicles. The epididmysis stores and collects sperm prior to ejaculation.