Question 1

Which of the following best describes the difference in signal travel between graded potentials and action potentials?

Accepted Answer

Graded potentials travel short distances in dendrites and cell bodies, while action potentials travel long distances along the axon.

Question 2

What is the threshold membrane potential required to initiate an action potential?

Accepted Answer

$-55\ \mathrm{mV}$

Question 3

Which statement about graded potentials is FALSE?

Accepted Answer

Graded potentials require a minimum threshold to occur.

Question 4

Action potentials are described as 'all-or-none' phenomena. What does this mean in terms of membrane potential?

Accepted Answer

Once the membrane potential reaches approximately $-55\ \mathrm{mV}$, the action potential always occurs.

Question 5

A neuron receives a stimulus that causes a depolarization to $-60\ \mathrm{mV}$. What will happen?

Accepted Answer

A graded potential will occur, but no action potential will be generated.

Question 6

Which of the following is TRUE regarding the location of graded potentials and action potentials?

Accepted Answer

Graded potentials occur in dendrites and cell bodies; action potentials occur in axons.

Question 7

If a stimulus causes a graded potential that does not reach the threshold, what is the result?

Accepted Answer

No action potential is generated, but the graded potential may affect the cell's activity.

Question 8

Which of the following best explains why action potentials do not vary in strength?

Accepted Answer

Action potentials are 'all-or-none' events; once threshold is reached, the amplitude is always the same.

Question 9

A patient has a mutation that raises the action potential threshold to $-40\ \mathrm{mV}$. What is the most likely effect?

Accepted Answer

Neurons will require a stronger stimulus to fire an action potential.

Question 10

Which of the following is a key difference between depolarization in graded potentials and action potentials?

Accepted Answer

Depolarization in graded potentials can vary in magnitude, while in action potentials it is always the same once threshold is reached.

Question 11

Which of the following scenarios best illustrates the concept of 'all-or-none' in action potentials?

Accepted Answer

A neuron fires an action potential only if the membrane potential reaches $-55\ \mathrm{mV}$, regardless of stimulus strength.

Question 12

Which of the following is NOT a characteristic of graded potentials?

Accepted Answer

They travel long distances along the axon.

Question 13

A researcher applies a stimulus to a neuron that results in a membrane potential change from $-70\ \mathrm{mV}$ to $-54\ \mathrm{mV}$. What will happen next?

Accepted Answer

An action potential will be generated.

Question 14

Which of the following best describes the role of the axon in action potentials?

Accepted Answer

The axon is the site of long-distance propagation of action potentials.

Question 15

If a neuron is exposed to a stimulus that causes hyperpolarization, what type of potential is most likely occurring?

Accepted Answer

Graded potential

Question 16

Which of the following is TRUE about the threshold for action potentials?

Accepted Answer

Action potentials require the membrane potential to reach approximately $-55\ \mathrm{mV}$.

Question 17

A neuron receives multiple graded potentials at its dendrites. What determines whether an action potential will be generated?

Accepted Answer

The sum of graded potentials must depolarize the membrane to at least $-55\ \mathrm{mV}$.

Question 18

Which of the following best explains why graded potentials can be larger or smaller?

Accepted Answer

Their amplitude depends on the magnitude of the stimulus.

Question 19

Which of the following is a correct statement about the propagation of action potentials?

Accepted Answer

Action potentials propagate in one direction along the axon due to the refractory period.

Question 20

A patient is exposed to a toxin that prevents the membrane potential from reaching $-55\ \mathrm{mV}$. What is the most likely effect?

Accepted Answer

Action potentials will not be generated.

Graded Potentials and Action Potentials in Neurons

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