Movement through cells

Hypotonic

Having a lower concentration of solute than another solution (think of hypothermia, body temp is BELOW needed)

isotonic

when the concentration of two solutions is the same

hypertonic

Having a higher concentration of solute than another solution. (hyperthermia, too HOT/ body temp is too HIGH)

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Osmosis

Diffusion of water through a selectively permeable membrane (movement of water from high to low concentration)

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference (low to high concentration)

channel proteins

provide corridors that allow molecules to cross the membrane, always open, non-discriminitory

carrier proteins

a protein that transports substances across a cell membrane, not always open, discriminatory

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

Endocytosis

the taking in of matter by a living cell by invagination of its membrane to form a vacuole.

Exocytosis

Process by which a cell releases large amounts of material

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Pinocytosis

process by which a cell takes in liquid from the surrounding environment

receptor-mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

aquaporins

channel proteins specific to water

what can pass through the membrane

Gasses, hydrophobic molecules (non-polar), small polar molecules

what cannot pass through the membrane

large polar molecules, charged molecules (ions)