Relate the concentration gradient of molecules to simple diffusion
Diffusion is the movement of molecules from high concentration to low concentration
Contrast between movement of nonpolar vs polar molecules across a membrane
o SMALL NONpolar (hydrophobic) molecules move FREELY across the membrane
o POLAR (hydrophilic) molecules CAN’T move freely across the membrane
Differentiate between simple diffusion and facilitated diffusion.
o Simple diffusion- the movement of molecules follows the concentration gradient (high->low) and pass through the membrane
o Facilitated diffusion- movement of molecules can go in either direction and pass through membrane using PROTEIN CHANNELS
Differentiate between channel proteins and carrier proteins.
o Channel proteins: create hydroPHILIC channels that allow molecules to pass through (each is specific for a specific molecule)
o Carrier proteins: bind specifically to molecules they assist (limited by # of transporters). undergo conformational change to transport
Predict the direction of water movement by osmosis.
Water will move where solvent concentration is higher to balance. (low to high/against concentration gradient)
Differentiate between hypertonic, hypotonic, and isotonic solutions
o Isotonic= solute concentration is the same in the cell and outside the cell
o Hypertonic= higher solute concentration OUTSIDE the cell vs inside the cell (cell SHRINKS)
o Hypotonic= higher solute concentration IN the cell vs outside the cell (cell SWELLS)
Explain osmotic pressure
The force needed to stop water from diffusion through a membrane by osmosis. When levels are equal so water doesn’t need to move across the membrane
