Chapter 13 Quiz

. Which substance is most directly responsible for exocytosis of synaptic vesicles?

Na⁺

Acetylcholine

K⁺

Ca²⁺

. Which statement regarding chemical synapses is true?

Chemical synapses are only excitatory.

Chemical synapses transmit information in two directions.

Chemical synapses have high plasticity.

Pre- and postsynaptic currents are always similar.

. What effect would injecting a leg muscle with a drug that binds to and disables acetylcholinesterase have on that leg?

Delayed paralysis

Immediate tetany

Tetany once the leg muscle was contracted

Paralysis once the leg muscle was contracted

. Ligand-gated channels on the postsynaptic membrane open and K⁺ and Na⁺ both move through these channels in opposite directions. Why then do we measure depolarization on the postsynaptic membrane?

Na⁺ has a much stronger driving force into the cell.

K⁺ has a much stronger driving force into the cell.

Na⁺ has a much stronger driving force out of the cell.

K⁺ has a much stronger driving force out of the cell.

. The main ion responsible for the EPSP is

Na⁺.

K⁺.

Cl^–.

Ca²⁺.

. The limiting factor in the synthesis of acetylcholine is the speed at which

acetyl groups are formed.

vesicles are formed.

choline is recycled.

vesicles release choline.

. The protein responsible for triggering the actual release of neurotransmitter at the synapse is

synaptotagmin.

SNARE.

dynamin.

sytaxin.

. Epinephrine is

excitatory.

inhibitory.

simultaneously excitatory and inhibitory.

either excitatory or inhibitory.

. Which statement regarding vertebrate neurotransmitters is true?

Most synapses (numerically) in the CNS use peptide neurotransmitters.

In the CNS, many receptors for biogenic amines mediate fast ionic responses.

Biogenic amines are found in almost all neurons in the CNS.

A neuroactive peptide may be co-released with one or more small-molecule neurotransmitters and may function as a cotransmitter.

. Which statement regarding metabotropic receptors is true?

They can directly open or close ion channels.

They always activate a G protein.

They use no second messengers.

They mediate membrane voltage changes via slow postsynaptic potentials.

. Which statement about the neuromuscular junction acetylcholine (Ach) receptor is false?

The probability an ACh channel will open depends on ACh concentration.

The synaptic current is the sum of the net ionic currents through all activated ACh receptors.

The opening of the ACh receptor is all-or-none.

The probability that an ACh channel will open depends on membrane voltage.

. Which protein cannot contact a G protein directly?

Protein kinase C

Potassium channel

Phospholipase C

Adenylyl cyclase

. During presynaptic inhibition, a(n)

metabotropic response reduces the number of action potentials reaching the synapse.

metabotropic response reduces the amount of calcium entering the nerve terminus.

ionotropic response reduces the number of action potentials reaching the synapse.

ionotropic response reduces the amount of calcium entering the nerve terminus.

. How often does a neuron's output equal its input?

All the time

Most of the time

Seldom

Never

. What is the relationship between synaptic facilitation and behavioral sensitization?

Synaptic facilitation is a short term response and behavioral sensitization is a long term response.

Synaptic facilitation is related to the sensory system and behavioral sensitization is related to the motor system.

Synaptic facilitation underlies behavioral sensitization.

They are both fundamentally the same thing.

. In Aplysia, the result of sensitization at the synapse is a(n)

decrease in the amount of neurotransmitter per impulse.

increase in the number of impulses per second.

increase in the amount of neurotransmitter per impulse.

decrease in the number of impulses per second.

. What is the mechanistic explanation for sensitization?

Increase in sodium flux

Increase in potassium flux

Decrease in potassium flux

Increase in calcium flux

. Calmodulin binds to _______ and becomes activated.

G protein

Ca²⁺

protein kinase C

adenylyl cyclase

. The induction of long-term potentiation occurs in the

presynaptic neuron.

synapse.

postsynaptic neuron.

motor neuron.

. Which statement best describes long-term potentiation?

More sodium entering the postsynaptic membrane per presynaptic action potential

More neurotransmitter released per action potential

More action potentials sent per second

More calcium released per action potential

Chapter 13 Quiz

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