Synaptic Transmission

Electrical synapses involve ___ whereas chemical synapses involve ___.

• direct electrical connections; release and reception of neurotransmitters
• direct electrical connections; release and reception of hormones
• indirect electrical connections; release and reception of neurotransmitters
• direct chemical connections; release and reception of hormones
• indirect chemical connections; release of electrical signals

What is the action of the neurotransmitter at a chemical synapse?

• It acts on receptors in the postsynaptic membrane.

• It electrically activates the presynaptic neuron

• It crosses the postsynaptic membrane and then activates ion channels in the postsynaptic neuron.

• It depolarizes the postsynaptic membrane by delivering an electrical charge.

• It transfers an action potential from the presynaptic neuron to the postsynaptic neuron.

Which event is the first in the series of events that take place during chemical synaptic transmission?

• Neurotransmitter binds to its receptors.

• Influx of Ca²⁺ in the presynaptic terminal.

• Voltage-gated Ca²⁺ channels open.

• Neurotransmitter is released into the synaptic cleft.

• Synaptic vesicles fuse with the presynaptic membrane.

At which point during signal transmission at a chemical synapse is exocytosis occurring?

• As neurotransmitter binds to its receptors.

• While Ca²⁺ enters the presynaptic terminal.

• As voltage-gated Ca²⁺ channels are opening.

• During neurotransmitter release into the synaptic cleft.

• During reuptake, as synaptic vesicles are reformed from the plasma membrane.

Tags

NGSS.HS-PS2-5

The figure shows an electron micrograph of a chemical synapse in the cerebral cortex. Which statement about this synapse is accurate?

• Inside the postsynaptic neuron are synaptic vesicles, which fuse with the membrane in the postsynaptic density.

• Inside the presynaptic neuron are synaptic vesicles, which fuse with the membrane in the active zone.

• Inside the presynaptic neuron are synaptic vesicles, which fuse with the membrane in the postsynaptic density.

• A gap junction connects the two neurons via connexons that span the pre- and postsynaptic membranes.

Small-molecule neurotransmitters are _______ for _______.

• taken back into the presynaptic terminal; degradation

• taken back into the presynaptic terminal; reuse

• taken up by the postsynaptic cell; degradation

• taken up by the postsynaptic cell; reuse

• scattered in the synaptic cleft; reuse

Tags

NGSS.HS-LS2-3

If the distribution of EPP amplitudes has peaks at 0.4 mV, 0.8 mV, 1.2 mV, 1.6 mV, and 2.0 mV, what is the most likely amplitude of the MEPP?

• 0.4 mV

• 0.8 mV

• 1.2 mV

• 1.6 mV

• 2.0 mV

How would application of a Ca²⁺ channel blocker affect the function of a synapse?

• It would increase the magnitude of postsynaptic potential.

• It would decrease the magnitude of postsynaptic potential.

• It would eliminate the postsynaptic potential but have no effect on presynaptic neuron.

• It would eliminate the postsynaptic potential and the presynaptic Ca²⁺ current.

• It would eliminate the presynaptic Ca²⁺ current but have no effect on the postsynaptic potential.