a difference in the concentration of a substance across a space
the process by which molecules move from an area of higher concentration to an area of lower concentration
movement of molecules through protein channels in the membrane from high to low concentration
The diffusion of water across a selectively permeable membrane
A double layer of phospholipids that forms the basis of all cellular membranes. The phospholipids heads, which are hydrophilic, face the water of extracellular fluid or the cytoplasm; the tails, which are hydrophobic, are buried in the middle of the bilayer.
pressure that must be applied to prevent osmotic movement across a selectively permeable membrane
describes a solution whose solute concentration is equal to the solute concentration inside a cell
describes a solution whose solute concentration is higher than the solute concentration inside a cell
describing a solution whose solute concentration is lower than that inside a cell
the movement of substances across a cell membrane without the use of energy by the cell
movement of molecules across a membrane requiring energy to be expended by the cell
process by which a cell takes material into the cell by infolding ( vesicle) of the cell membrane.
process by which vesicles release their contents outside the cell