Under certain circumstances, potassium ions ( K + ) in a cell will move across the cell membrane from the inside to the outside. The potential inside the cell is − 70.5 mV and the potential outside the cell is zero. What is the change in the electrical potential energy of a single potassium ion as it moves across the membrane?

8.18 × 10 ⁻²¹.

Explanation:

The potential energy may be defined as the energy stored in the rest objects. This energy is important for the maintenance of the concentration gradient in the cell.

The change in the potential energy can be calculated as follows:

W = v2-v1 × q.

Here, the charge of the proton is considered because k+ ions has been used.

W= 0 - ( - 70. 5 mV) × 1.602 * 10^-19 C.

W= 8.18 × 10 ⁻²¹J.

Thus, the answer is 8.18 × 10 ⁻²¹.