Passive transport
The movement of substances across a cell membrane without the use of energy by the cell
Active transport
Movement of chemical substances, usually across the cell membrane from area of lower concentration to an area of higher
-"up" concentration gradient
-requires a cell to expend energy
Osmosis
Process by which water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration
-does not require cells to expend energy
-passive transport of water
Facilitated diffusion
Process is used for molecules that cannot readily diffuse through cell membranes, even when there is s concentration gradient across the membrane
-another type of passive transport
-the movement of these kinds of molecules across cell membrane
Sodium-potassium pump
An example of active transport in animal cells that involves a carrier protein
-stages:
�three Na+ ions located in the cytosol bind to the carrier protein
�phosphate group removed from ATP and bound to carrier protein
�binding of phosphate group changes s
Endocytosis
The progress by which cells ingest external fluid, macromolecules, and large particles, including other cells
-two types based of kind of material:
�pinocytosis (involves transport of salutes or fluids)
�phagocytosis (movement of large particles or whole
Exocytosis
The process by which a substance is released from the cell through a vesicle that transports the substances to cell surface and the fuses with membrane to let substances out of cell
-cells may use to release large molecules such as proteins, waste product