Q$3$ Neurons

$5$ Points

Grading comment:

You have decided to study the effect of different drugs on membrane potential.

Question $3\mathrm{.}1$

Q$3\mathrm{.}1$

$1$ Point

Grading comment:

Which of those proteins we reviewed as critical for the neuronal membrane potential would be affected by depleting all neural ATP?

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Question $3\mathrm{.}1$:

Question $3\mathrm{.}2$

Q$3\mathrm{.}2$

$1$ Point

Grading comment:

What would happen to the neuronal membrane potential when we treat neurons with a drug that opens all voltage$-$gated K channels?

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Question $3\mathrm{.}2$:

Question $3\mathrm{.}3$

Q$3\mathrm{.}3$

$1$ Point

Grading comment:

You study the effect of drug A that binds to voltage$-$gated ion channels. The action potential of neurons treated with drug A lasts longer than those in untreated neurons. What are the two possible explanations for this change in action potential shape.

Give $2$ possible explanations

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Question $3\mathrm{.}3$:

Question $3\mathrm{.}4$

Q$3\mathrm{.}4$

$1$ Point

Grading comment:

What would be the effect of a toxin that binds specifically to voltage$-$gated sodium channels in axons? $($indicate the effect on the action potential$)$

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Question $3\mathrm{.}4$:

Question $3\mathrm{.}5$

Q$3\mathrm{.}5$

$0\mathrm{.}5$ Points

Grading comment:

Action potentials are normally carried in only one direction: from the axon hillock toward the axon terminals. What would happen if you experimentally depolarize the middle of the axon to threshold, using an electronic probe?

Choice $1$ of $5$:no action potential will be initiated.Choice $2$ of $5$:an action potential will be initiated and proceed only in the normal direction toward the axon terminal.Choice $3$ of $5$:an action potential will be initiated and proceed only back toward the axon hillock.Choice $4$ of $5$:two action potentials will be initiated, one going toward the axon terminal and one going back toward the hillock.Choice $5$ of $5$:an action potential will be initiated, but it will die out before it reaches the axon terminal.

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Question $3\mathrm{.}5$:

Question $3\mathrm{.}6$

Q$3\mathrm{.}6$

$0\mathrm{.}5$ Points

Grading comment:

The steps below refer to various stages in transmission at a chemical synapse: $1.$ Neurotransmitter binds with receptors associated with the postsynaptic membrane. $2.$ Calcium ions rush into neuron's cytoplasm. $3.$ An action potential depolarizes the membrane of the axon terminal. $4.$ The ligand$-$gated ion channels open. $5.$ The synaptic vesicles release neurotransmitter into the synaptic cleft.

Which sequence of events is correct?

Choice $1$ of $5$:$12345$Choice $2$ of $5$:$23541$Choice $3$ of $5$:$32514$Choice $4$ of $5$:$43125$Choice $5$ of $5$:$51243$