Question

Why is the sodium potassium pump an example of active transport?

Answer 1

Active transport is defined as the movement of molecules across a cell membrane against the concentration gradient, from a region of lower concentration to a region of higher concentration. Cellular energy is required in active transport to achieve this movement. The 2 types of active transport are the primary active transport and the secondary active transport. The former uses adenosine triphosphate (ATP) as an energy source, and the latter uses an electrochemical gradient.

Complete explanation:
The sodium potassium pump, also known as Na-K ATPase is a transmembrane protein present in the membrane of all animal cells. The sodium potassium pump helps in maintaining the resting potential of the cell and also regulates cellular volume. Resting potential means cells keep a low level of sodium ions and high levels of potassium ions to maintain equilibrium.
The purpose of Na-K ATPase is to move sodium and potassium ions across the cell membrane. It means, during each cycle three sodium ions move out for every two potassium ions brought in. This unbalanced charge transfer leads to the separation of charges across the cell membrane. The pumping process requires hydrolysis of ATP to provide the necessary energy and so it is considered an example of active transport.

Note:
Another type of membrane transport called passive transport does not require energy to move substances across cell membranes. Passive transport works in accordance with the second law of thermodynamics where substances move from a region of higher concentration to that of lower concentration spontaneously. The rate of passive transport is determined by the permeability of the cell membrane.