Action Potential

Q. When a stimulus is applied at a site on the polarised membrane:

1. $N{a}^{+}$ moves out of axoplasm
2. $N{a}^{+}$ moves into axoplasm
3. $K^{+}$ moves into axoplasm
4. $C{a}^{2+}$ moves into axoplasm

Q. During repolarisation of nerve

1. $N{a}^{+}$ channels close and $K^{+}$ channels are open
2. $K^{+}$ gate close and $N{a}^{+}$ gate opens
3. Both gates remain open
4. Bth $K^{+}$ and $N{a}^{+}$ gates are close

Q. Match the following stages of action potential to its corresponding state of ion movement

I. Depolarization stage (p). (K⁺) ions move outside the cell
II. Repolarization stage (q). (Na⁺) ions move inside the cell
III. Hyperpolarization stage (r). No net ion movement
IV. Resting stage (s). (K⁺) ions move into the cell
V. Threshold potential (t). Ligand gated sodium channels open
VI. Stimulus reaches the neuron (u). Voltage gated sodium channels open

1. I. (p), II. (u), III. (q), IV. (r), V. (s), VI. (t)
2. I. (q), II. (p), III. (s), IV. (r), V. (u), VI. (t)
3. I. (s), II. (p), III. (p), IV. (t), V. (u), VI. (r)
4. I. (p), II. (s), III. (r), IV. (u), V. (t), VI. (q)

Q. Choose the correct order of changes in the potential on the inner side of the neuronal membrane during transmission of a nerve impulse.

1. First negative, then positive and continues to be positive
2. First positive, then negative and continues to be negative
3. First positive, then negative and again back to positive
4. First negative, then positive and again back to negative

Q. Permeability of which of the following increases during depolarization?

1. $N{a}^{+}$
2. $K^{+}$
3. Both $N{a}^{+}$ and $K^{+}$
4. None of the above

Q. When a stimulus is applied at a site on the polarised membrane:

1. $N{a}^{+}$ moves out of axoplasm
2. $N{a}^{+}$ moves into axoplasm
3. $K^{+}$ moves into axoplasm
4. $C{a}^{2+}$ moves into axoplasm

Q.

Depolarization of axolemma during nerve conduction takes place because _____.

1. Equal amount of Na⁺ and K⁺ move across the axolemma

2. Na⁺ ions move inside

3. More Na⁺ ions outside

4. More K⁺ ions outside

Q. Which of the following is correct about generation and conduction of nerve impulse?

1. The electrical potential difference across the resting plasma membrane is called the action potential
2. At resting phase, the axonal membrane is comparatively more permeable to potassium ions $\left(K^{+}\right)$ and nearly impermeable to sodium ions $\left(N{a}^{+}\right)$
3. The ionic gradients across the resting membrane are maintained by the active transport of ions by the sodium-potassium pump which transports $2N{a}^{+}$ outwards for $3K^{+}$ into the cell
4. Depolarization is due to rapid influx of potassium ions

Q.

Fill in the correct sequence for generation of Action potential in a neuron

Stimulus ⟶Inflow of $N{a}^{+}$ ions ⟶ _(i)_____⟶Repolarisation ⟶___(ii)______

1. (i) Transmission of $N{a}^{+}$, (ii) Inflow of $N{a}^{+}$ ions

2. (i) Inflow of $N{a}^{+}$ ions, (ii) Transmission of $N{a}^{+}$

3. (i) Transmission of $N{a}^{+}$ & $K^{+}$ , (ii) Hyperpolarization & RMP

4. (i) Hyperpolarization, (ii) Inflow of $N{a}^{+}$ ions

Q. Action potential results from the movement of

1. ${\mathrm{Na}}^{+}$ from intracellular fluid to extracellular fluid
   
2. ${\mathrm{Na}}^{+}$ from extracellular fluid to intracellular fluid
3. ${\mathrm{Na}}^{+}$ in both directions
4. Stagnation of ${\mathrm{Na}}^{+}$ ions

Q. Match the column I and column II and choose the correct option.
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{A.Synapse}& \text{I. Opening of sodium channels}\\ & \text{resulting in rapid influx of sodium}\\ & \text{and closing of sodium channels.}\\ \text{B.Repolarization phase}& \text{II. The electrical potential difference}\\ & \text{across the resting plasma membrane.}\\ \text{C. Resting Potential}& \text{III. The site of transmission of electric}\\ & \text{nerve impulses between two neurons.}\\ \text{D. Depolarization}& \text{IV. Opening of potassium channels}\\ & \text{and rushing out of potassium.}\end{array}$

1. A-II, B-I, C- IV, D-III
2. A-III, B- I, C- II, D- IV
3. A-III, B-IV, C-II, D-I
4. A-IV, B-II, C-I, D-III

Q. Ions diffuse freely along their (i)___, from the region of (ii)___ concentration and (iii)___ charge to the region of (iv)___ concentration and (v)___charge.

1. (i) concentration gradient, (ii) high, (iii) opposite, (iv) low, (v) similar
2. (i) electrochemical gradient, (ii) high, (iii) opposite, (iv) low, (v) similar
3. (i) concentration gradient, (ii) high, (iii) similar, (iv) low, (v) opposite
4. (i) electrochemical gradient, (ii) high, (iii) similar, (iv) low, (v) opposite

Q.

Threshold potential is a state of depolarisation at which _____.

1. An action potential is sure to fire

2. Voltage gated Na+ channels open

3. Membrane potential is near -55mV

4. All of the above

Q. Refer the figure to answer the question. Identify the region where all $N{a}^{+}$ channels are reactivated, but closed and all $K^{+}$ channels are closed.

1. D
2. C
3. B
4. A

Q.

How does the membrane potential inside a neuron change during an action potential?

1. First positive, then negative and continue to be negative

2. First negative, then positive and continue to be positive

3. First positive, then negative and again back to positive

4. First negative, then positive and again back to negative

Q.

How does the membrane potential inside a neuron change during an action potential?

1. First positive, then negative and continue to be negative

2. First negative, then positive and continue to be positive

3. First positive, then negative and again back to positive

4. First negative, then positive and again back to negative