3.4 Diffusion And Osmosis Flashcards
is the movement of molecules in a fluid or gas from a region of higher concentration to a region of lower concentration
Diffusion
is the move- ment of molecules across a cell membrane without energy input from the cell. It may also be described as the diffusion of molecules across a membrane.
Passive transport
is the difference in the concentration of a substance from one location to another
Concentration gradient
Water molecules, of course, also diffuse. They move across a semipermeable membrane from an area of higher water concentration to an area of lower water concentration. This process is called
Osmosis
to a cell if it has the same concentration of dis- solved particles as the cell. Water molecules move into and out of the cell at an equal rate, so the cell’s size remains constant.
Isotonic
solution has a higher concentration of dissolved particles than a cell.
Hypertonic
solution has a lower concentration of dissolved particles than a cell.
Hypotonic
is the diffusion of molecules across a membrane through transport proteins
Facilitated diffusion