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).
For human transport systems, see active transportation. Active transport is the movement of molecules across a cell membrane from a region of their lower concentration to a region of their higher concentration -- in the direction against some gradient or other obstructing factor (often a concentration gradient).