What Is Active And Passive Transport?

Active transport is the movement of solutes against concentration gradient or electrical gradient.  The solute pass from low solute concentration to the higher solute concentration therefore it is also known as uphill transport depends upon the sites on in repulsion and attracts negative charges.

Active transport is an energy dependent process that requires ATPs. The phenomenon of active transport cell   membranes is dependent upon the presence of specific protein carriers.

Examples of Active Transport includes Sodium pumps in cells: the cells pump out Na+ from the intracellular space in the extra cellular space, which has a high concentration of Na+. This pumping out of Na+ by the cells is against the concentration gradient and utilizes ATP.
Secretion of H+ B ions by the oxyntic cells of the gastric glands.   Reabsorption of glucose from the proximal convoluted tubules of the kidney.Active uptake of iodide by the cells of the thyroid gland.

Passive transport is the movement of solutes towards the concentration gradient or electrical gradient. The solute pass from high solute concentration to the low solute concentration therefore it is also known as downhill transport. The energy required for the passive transport is not derived from ATPs rather from the random motion of the molecules themselves. Smaller the size of the substance, more rapid will be its transport.