Bio Validation Flashcards
diffusion
the movement of molecules from an area of high concentration to low concentration
diffusion only occurs when
there is a concentration gradient (a difference in concentration between the two areas)
diffusion is a
passive process (does not require the expenditure of energy)
diffusion can occur in
almost any circumstance where molecules can move (not only in cells)
diffusion in cells
molecules will diffuse across the cell membrane if they are small enough to fit through the gaps between the lipids
once there is no concentration gradient
the end or net result is no change
molecules that pass thorough the lipid bilayer by diffusion
oxygen, carbon dioxide, alcohol
osmosis
a case of diffusion that involves the diffusion of water across a cell membrane
water molecules are
very small and pass through the semipermeable membrane very easily
osmosis occurs when
water moves from an area of high concentration of water to an area of low concentration of water
cell membranes are described as being
semipermeable/selectively permeable/differentially permeable
semipermeable means that
they allow some ions and molecules to pass through, but restrict the movement of others. this is usually based on size
hypotonic
when the solution has fewer solute particles than the cell, thus there is a net inflow of water.
hypertonic
when the solution has a greater concentration of solute particles than the cell. thus there is a net outflow of water.
isotonic
solution has the same concentration of solutes as the cell, thus there is no net flow of water.
