Chapter 7 Flashcards
amiphipathic molecule
both water loving (hydrophillic) and water fearing (hydrophobic) regions
fluid mosaic model
membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids
integral proteins
penetrate the hydrophobic interior of the lipid bilayer
transmembrane proteins
spam the membrane
peripheral proteins
not embedded in the lipid bilayer at all; loosely bound to the surface of the membrane
selective permeability
allows some substances to cross more easily than others
diffusion
the movement of particles of any substance so that they spread out into the available space
concentration gradient
region along which the density of a chemical substance increases or decreases
passive transport
diffusion of a substance across a biological membrane
osmosis
diffusion of free water across a selectively permeable membrane, whether artificial or cellular
tonicity
the ability of a surrounding solution to cause a cell to gain or lose water
isotonic
iso (same; no net movement of water across the plasma membrane
hypertonic
hyper (more water)
hypotonic
hypo (less water)
osmoregulation
the control of solute concentrations and water balance