Question

In the resting state, the axonal membrane is ___(i)____ with more ___(ii)___ charged ions outside than inside. This unequal distribution of ions is due to (1) the selective permeability of the membrane, which forms an almost impenetrable barrier to ___(iii)___ and (2) the action of the ____(iv)___, which pumps ___(v)___ Na${}^{+}$ out of the neuron for every ____(vi)___ K${}^{+}$ brought in.
Select the option that correctly fills the blanks in the paragraph.

• A. (i) - depolarised, (ii) - positively, (iii) - Na${}^{+}$, (iv) - sodium - potassium pump, (v) - three, (vi) - two
• B. (i) - depolarised, (ii) - negatively, (iii) - Na${}^{+}$, (iv) - sodium - potassium pump, (v) - three, (vi) - two
• C. (i) - polarised, (ii) - negatively, (iii) - Na${}^{+}$, (iv) - sodium - potassium pump, (v) - three, (vi) - two
• D. (i) - polarised, (ii) - positively, (iii) - Na${}^{+}$, (iv) - sodium - potassium pump, (v) - three, (vi) - two

Answer 1

The correct option is D (i) - polarised, (ii) - positively, (iii) - Na${}^{+}$, (iv) - sodium - potassium pump, (v) - three, (vi) - two

In the resting state, the axonal membrane is polarised with more positively charged ions outside than inside, unequal distribution of ions is due to the selective permeability of the membrane, which forms impermeable barrier to sodium ion and the action of the sodium which pumps three sodium ions out of the neuron for every two potassium ions brought in.

Thus, the correct option is '(i) - polarised, (ii) - positively, (iii) - Na${}^{+}$, (iv) - sodium - potassium pump, (v) - three, (vi) - two.'