Cell Function Vocab3/30/09

VOCABULARY concentration gradient – concentration at various points

between the highest and lowest concentrations diffusion – movement of molecules from high to low

concentration osmosis – movement of water through a membrane endocytosis – movement of substances INTO a cell exocytosis – movement of substances OUT of a cell plasmolysis – condition where a cell collapses because water

is diffusing out cytolysis – condition where a cell bursts because of water

diffusing in (occurs in animal cells) turgor pressure – condition where water pressure in the

vacuole of a plant cell pushes out against the cell walls

VOCABULARY tonicity – comparison of the relative concentrations of

solutions hypertonic – a solution that has more solutes hypotonic – a solution that has less solutes isotonic – solutions that have equal solutes (homeostasis,

balance, equilibrium) permeability – ability of a membrane to allow molecules to

pass through selectively (semi) permeable – only some molecules can

pass through permeable – all molecules can pass through impermeable – no molecules can pass through