Chapter 5 practice quiz

Identify the neuroscientists who first proved the existence of electrical synapses. Choose the correct option.

Edwin Furshpan and David Potter

What types of cells can a neuron communicate with at a synapse? Choose the correct option.

Another neuron, muscle cell, or glandular cell

What is the function of a gap junction between neurons? Choose the correct option.

Electrical synapse between the neurons

What is the other name for dense-core vesicles? Choose the correct option.

Secretory granules

Why are neuromuscular junctions such reliable synapses? Choose the correct option.

Because the axon terminal is large and the presynaptic terminal contains a large number of active zones

What are transporters? What is their role? Choose the correct option.

Special proteins embedded in the vesicle membrane; responsible for concentrating neurotransmitters inside the vesicle

Which of the following channels in the active zones of the synaptic terminal open when the membrane depolarizes and causes the release of synaptic vesicles? Choose the correct option.

Voltage-gated calcium channels

Under what conditions are peptide neurotransmitters generally released from the synaptic terminal? Choose the correct option.

Only with high-frequency trains of action potentials

What are second messengers? Choose the correct option.

Molecules that activate additional enzymes in the cytosol

How are released neurotransmitters cleared from the synaptic cleft? Choose the correct option.

Enzymatic destruction and diffusion

How do nerve gases interfere with synaptic transmission at the neuromuscular junction? Choose the correct option.

By inhibiting the enzyme AChE

What is synaptic integration? Choose the correct option.

A process by which multiple synaptic potentials combine within one postsynaptic neuron

Quantal analysis shows that a single action potential at the neuromuscular junction causes an EPSP of 40 mV or more, compared to only a few tenths of a millivolt at many CNS synapses. What accounts for this difference? Choose the correct option.

A larger number of synaptic vesicles releasing neurotransmitter at the neuromuscular junction compared with CNS synapses

What is the effect of activating G-protein-coupled neurotransmitter receptors? Choose the correct option.

Activate effector proteins such as ion channels or those that synthesize second messengers

Protein phosphorylation can change the conformation of a protein, thereby changing its activity. True or false?

True

If the postsynaptic cell is an interneuron that uses GABA as a neurotransmitter, the excitation of the cell will result in an action potential in its synaptic targets. True or false?

False

The effectiveness of an excitatory synapse in triggering an action potential depends on how near the synapse is to the spike-initiation zone and the properties of the dendritic membrane. True or false?

False

Second messengers can alter cellular metabolism by activating additional enzymes in the cytosol. True or false?

True

Opening of the chloride channel allows Cl- ions to cross the membrane, bringing the membrane potential toward the ___________ equilibrium potential, ECl, about -65 mV. If the membrane potential was less negative than -65 mV when the transmitter was released, the activation of these channels would cause a ___________________ IPSP.

chloride, hyperpolarizing

Most neurotransmitters fall into one of the three chemical categories: _____________, ___________, and _____________.

amino acids, amines, peptides

Which of the following would be the LEAST practical as a neurotransmitter molecule?

A large modified protein

As the action potential reaches the axon terminal, the release of synaptic vesicles containing neurotransmitter would be directly triggered by:

Influx of Ca++ ion into the cell

An electrical synapse between two neurons could involve the following EXCEPT

Release of neurotransmitters from the presynaptic cell

Unlike the synaptic vesicles, the dense core vesicles:

Contain small proteins or peptides

GPCRs (G-protein coupled receptors)

Can activate a number of effector proteins

Which of the following synapse types would only be able to use electrical synapses (and not involve release of neurotransmitters from vesicles)?

dendrodendritic

Acetylcholine is a neurotransmitter molecule that is:

derived from an amine molecule

Generating an EPSP would involve hyperpolarization of the postsynaptic cell. True or False?

False

A receptor agonist will mimic the effect of the neurotransmitter that normally stimulates the receptor. True or False?

True

During temporal integration, EPSPs are added simultaneously but at different locations on post synaptic neuron. True or False?

False