33 terms

Cell membrane and transport

a lipid made of a phosphate head and two fatty acid tails
lipid bilayer
cell membranes composed of two layers of phospholipids, with the tails pointed inwards towards each other, and the heads facing outward
cell surface markers
a membrane protein that identifies the cell type
receptor proteins
a membrane protein that binds to signals outside the cell
transport proteins
transports substances unable to diffuse across a cell membrane
active transport
energy is required to move a substance across a cell membrane
passive transport
no energy is required to transport substances across cell membranes
when randomly moving molecules fill up a space evenly
the amount of a particular substance in a given volume
concentration gradient
a difference in the concentration of a substance across a distance
substances moving down the concentration gradient (from high to low concentration)
simple diffusion
small, nonpolar molecules passing directly through the lipid bilayer
facilitated diffusion
transport proteins helping ions and polar molecules to diffuse through the bilayer
channel proteins (pores)
tunnels that open for ions and polar molecules to pass through the cell membrane
carrier proteins
a protein that transports substances across a cell membrane by changing shape
the process of water diffusing across a selectively permeable membrane
water channels
channel proteins that aid in osmosis, and only allow water molecules to pass through
hypertonic solution
the solute has high concentration, the water has low, water moves out of the cell
hypotonic solution
the solute has low concentration, the water has high, water moves into the cell
isotonic solution
the solute and water have an equal concentration to the cell's cytoplasm, water moves into and out of the cell at equal rates
contractile vacuoles
colllect excess water in unicellular eukaryotes and force the water out of the cell
sodium-potassium pump
a carrier protein that uses ATP to actively transport 3 sodium ions out of a cell, and 2 potassium ions into a cell
the process of a large substance moving into a cell using a vesicle
the process of a large substance moving out of a cell by means of a vesicle
anything that serves to direct, guide or warn
target cell
a cell that responds to a signal sent by a signaling cell
receptor proteins
a protein that binds to specific signal molecules, causing the cell to respond
permeability change
transport proteins opening or closing in response to a signal
A term used to describe plant tissue where the cells have lost turgor and are not firm.
The pressure that water molecules exert against the cell wall
swollen as from a fluid; bloated
Another term that describes the concentration of solution