The basic structure of the cell membrane, formed by two layers of phospholipids with hydrophilic heads facing outwards and hydrophobic tails facing inwards
A spherical structure formed when phospholipids are mixed with water, with the hydrophilic heads facing outwards and the hydrophobic tails facing inwards
A lipid that is a component of animal cell membranes, positioned between phospholipids with its hydrophobic region interacting with the phospholipid tails and its hydrophilic hydroxyl group interacting with the phosphate heads
The net movement, as a result of the random motion of its molecules or ions, of a substance from a region of its higher concentration to a region of its lower concentration
As a result of diffusion, molecules or ions tend to reach an equilibrium (given sufficient time), where they are evenly spread within a given volume of space
Smaller polar molecules (e.g. urea) can diffuse at low rates, although larger polar molecules cannot easily pass through the hydrophobic part of the membrane
During facilitated diffusion, the net diffusion of molecules or ions into or out of a cell will occur down a concentration gradient (from an area containing many of that specific molecule to an area containing less of that molecule)
The solute concentration of a solution; a solution with high osmolarity has a high solute concentration and a solution with low osmolarity has a low solute concentration