Passive and Active Transport

contractile vacuole

gets rid of excess water in the cell (paramecium)

passive transport

membrane transport that does not require energy to move substances across cell membranes

hypotonic

The solution has less solute than the cell, water will move into the cell and solute out (if it can pass through membrane)

plasmolysis

the cell shrinks ( more flaccid) because water is moving out of the cell

diffusion

the net movement of anything from a region of higher concentration to a region of lower concentration

hypertonic

The solution has more solute than the cell, water will move out of the cell and solute in (if it can pass through membrane)

cytolysis

the cell swells (more turgid) because water is moving into the cell

concentration gradient

occurs when the concentration of particles is higher in one area than another.

Isotonic

the solution has equal solute to the cell, water will move in and out of the cell maintaining dynamic equilibrium and the solute will do the same (if it can pass through the membrane)

facilitated diffusion

the diffusion of solutes through transport proteins in the plasma membrane

equilibrium

The condition in which all acting influences are balanced or canceled by equal opposing forces, resulting in no net change

carrier protein

transports certain biomolecules between cells

osmosis

movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell's partially permeable membrane.

turgor pressure

pressure that is exerted by the fluid (e.g. water) that pushes the plasma membrane against the cell wall

ion channel

pores in the cellular membrane that allow the passage of ions across the cell membrane

active transport

a process that involves the movement of molecules from a region of lower concentration to a region of higher concentration against a gradient or an obstacle with the use of external energy

pinocytosis

endocytosis when material taken in is a liquid

sodium-potassium pump

It acts to transport sodium and potassium ions across the cell membrane in a ratio of 3 sodium ions out for every 2 potassium ions brought in

phagocytosis (amoeba)

endocytosis when the material taken in is a bacterial cell or an organic fragment (food)

endocytosis

material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested material

phagocyte

a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles

vesicle

a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. They form naturally during the processes of secretion, uptake and transport of materials within the plasma membrane.

exocytosis

a process by which the contents of a cell vesicle are released to the exterior through fusion of the vesicle membrane with the cell membrane