Cell membrane transport

cell membrane

thin, flexible barrier around a cell; regulates what enters and leaves the cell

homeostasis

process by which organisms maintain a relatively stable internal environment

phospholipid

A lipid made of a phosphate group and two fatty acids; consists of a hydrophilic polar head and two non-polar hydrophobic tails; forms cell membranes.

lipid bilayer

a thin membrane made of two layers of lipid molecules

diffusion

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

osmosis

diffusion of water through a selectively permeable membrane

passive transport

The movement of materials through a cell membrane without using energy

hypertonic solution

in cells, solution in which the concentration of dissolved substances outside the cell is higher than the concentration inside the cell; causes a cell to shrink as water leaves the cell

hypotonic solution

in cells, solution in which the concentration of dissolved substances is lower in the solution outside the cell than the concentration inside the cell; causes a cell to swell and possibly burst as water enters the cell

isotonic solution

in cells, solution in which the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside a cell

active transport

energy-expending process by which cells transport materials across the cell membrane against a concentration gradient

endocytosis

The process by which cells ingest external fluid, macromolecules, and large particles, including other cells

exocytosis

active transport process by which materials are secreted or expelled from a cell

facilitated diffusion

the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins

hydrophobic

repelled by water

hydrophilic

attracts water molecules

pinocytosis

cell drinking

equillibrium

a condition in which molecules are spread evenly(equally)

concentration gradient

difference in concentration of a substance on two sides of a membrane

sodium-potassium pump

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

Phagocytosis

Cell eating (taking in solid materials)