The net movement of molecules from a higher concentration to an area of lower concentration until equilibrium is reached, does not require ATP
Facilitated diffusion
Carrier proteins and protein channels are used to transport ions and polar molecules across the membrane, does not require ATP
Osmosis
The movement of water from an area of higher water potential to an area of lower water potential across a partially permeable membrane
Isotonic solution
The water potential of the solution is the same as the cell, no net movement will occur
Hypertonic solution
The water potential of the solution is more negative than the cell, water moves out of the cell by osmosis
Hypotonic solution
The water potential of the solution is more positive than the cell, water will move into the cell by osmosis
Active transport
The movement of molecules and ions from an area of lower concentration to an area of higher concentration (against the concentration gradient) using ATP and carrier proteins
Endocytosis
The cell surface membrane bends inwards around the molecule surrounding it to form a vesicle, the vesicle pinches off and moves within the cytoplasm, requires ATP
Exocytosis
Vesicles move towards the cell-surface membrane, fuse with the membrane and the contents of the vesicle is released outside of the cell, requires ATP
