Mrs. Mayer Ch: 5 Transport and Homestasis

Passive Transport

movement of substances across a cell membrane without using any energy

Diffusion

movement of molecules from an area of higher concentration to an area of lower concentration

Concentration gradient

difference in the concentration of molecules across a space

Equilibrium

concentration of molecules of a substance is the same throughout a space

Osmosis

process by which water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration

Hypotonic

concentration of solute molecules outside the cell is lower than the concentration inside the cell

Hypertonic

concentration of solute molecules outside the cell is higher than the concentration inside the cell

Isotonic

concentrations of solutes outside and inside the cell are equal

contractile vacuole

collects excess water and pumps it out

turgor pressure

pressure that water molecules exert against the cell wall

plasmolysis

in a hypertonic environment, water leaves the cells and the cells shrink away from the cell wall and turgor pressure is lost

cytolysis

bursting of cells

Facilitated Diffusion

movement of molecules from a higher concentration to a lower concentration by using carrier proteins

Carrier proteins

protein in cell membrane that moves molecules across the membrane

Ion channel

small passageways across the cell membrane through which ions can diffuse

Active Transport

requires energy to move material from an area of lower concentration to an area of higher concentration

Sodium-Potassium pump

three Na+ pumped outside and two K+ are pumped inside

Endocytosis

process by which cells ingest large particles or other cells

pinocytosis

solutes or fluids taken in

phagocytosis

large particles, cells, or bacteria (phagocytes) taken in

Exocytosis

process in which particles are expelled or removed from the cell