Some substances are allowed to pas through and others cannot. The cell membrane is this.
Molecules move through the cell membrane from an area of higher concentration to lower concentration.
WATER molocules use diffusion to move across a selectivly permeable cell membrane. (higher to lower concentration)
When molecules are transported WITHOUT USING cellular energy.
When molecules are transported while USING cellular energy.
types of passive transport
osmosis and diffusion
types of active transport
carrier proteins and engulfing