Active transport requires the use of ATP because in active transport things move against the concentration gradient. Usually there is a protien pump (which is a form of a transport protien) that does...
Yes ! Active Transport is the movement of molecules from an area of low concentration to high concentration against equilibrium. Active transport requires energy and a transport protein.
Because there is a higher concentration inside the cell then out side ....because it requires energy to move the molecules outside in a different direction then they would normally move, it is like...