Question

Ion X+ is sitting outside of a cell. Which of the following scenarios will cause ion X+ to move into a cell?

A) High concentration of a negative ions inside the cell, and low concentration of X+ inside the cell.

B) Low concentration of negative ions inside the cell, and high concentration of X+ inside the cell.

C) Low concentration of positive ions outside the cell, high concentration of X+ outside the cell.

D) High concentration of negative ions outside the cell, low concentration of X+ inside the cell.

Answer 1

The correct answer is option B.

Explaination:- The movement of ions across the cell occurs through active transport, i.e, against the concentration gradient. Therefore, for X+ ion to move into a cell requires low concentration of negative ions inside the cell and high concentration of X+ inside the cell. This will require energy in the form of ATP to move against the concentration gradient.

The other options are an example of passive transport which is the movement of molecules along the concentration gradient.

Therefore, the correct answer is option B.