Question

The Na+-K+ ATPase uses the free energy of ATP hydrolysis in an active transport process to move Na+ and K+ across a membrane. What would the rate of nonmediated transport be given that the permeability coefficient for K+ through a human erythrocyte membrane is 2.4 × 10-10 cm/s. K+ ions must be moved from a concentration of 4 mM on the outside of the cell to 155 mM inside the cell?

Answer 1

Answer: The rate of non-mediated transport is
`-362.4 * 10^(-10)` mM/s.

Step-by-step explanation:

Formula to calculate non-mediated transport is as follows.

J =
`-P(C_(2) - C_(1))`

where, J = net rate of transportation

P = permeability coefficient =
`2.4 * 10^(-10)` cm/s

`C_(2)` = higher concentration region = 155 mM

`C_(1)` = low concentration region = 4 mM

Putting the given values into the above formula as follows.

J =
`-P(C_(2) - C_(1))`

J =
`-(2.4 * 10^(-10))(155 - 4)`

=
`-362.4 * 10^(-10)` mM/s

Therefore, we can conclude that the rate of non-mediated transport is
`-362.4 * 10^(-10)` mM/s.