In biological systems, there are several membrane transport systems responsible for the passage of ions like Na+ and K+ , or small molecules like glucose and amino acids, through biological membranes. Classify each membrane transport system as either a primary active transporter, a secondary active transporter, or a passive transporter. Which transport systems utilize a chemical reaction for the energy source?

Cell membranes are barriers which protect and regulate the movement of substances in and out of the cells. It is a semi-permeable and selective structure.

In the passive transport system, substances move along a concentration gradient and it doesn't require energy. The examples of passive transports include; simple diffusion which transports carbon dioxide and oxygen, osmosis and facilitated diffusion which transports charged molecules like ions, sucrose etc.

In active transport, substances move against the concentration gradient. This requires energy. The two main types are: primary active transport, which uses direct metabolic energy e.g Na+/K+ pump, and the secondary active transport system which couples the transported molecules with another molecule moving along the gradient, example the Na+/glucose transporter.