claim the interaction of motrin and robitussin can cause heart attacks in children
Active transport. Active transport is the movement of molecules across a cell membrane from a region of their lower concentration to a region of their higher concentrationâin the direction against some gradient or other obstructing factor (often a concentration gradient).
This is called passive transport. Active transport therefore is the movement of a substance or substances against its concentration gradients. This usually happens when the cells need high concentrations of molecules like when glucose is transported to the intestines and when mineral ions are transported to the roots of plants.