Biology 2:cells - diffusion,osmosis and active transport Flashcards
name 5 ways of moving across a membrane
simple diffusion
facilitated diffusion
omosis
active transport
co-transport
what is simple diffusion and what does it happen through
net movement of particles down the concentration gradient
happens through lipid bilayer(non polar molecules)
name 5 things diffusion if affected by
concentration gradient
surface area to volume ratio
membrane thickness(diffusion distance)
polarity
temperature
what is ficks law
rate of diffusion = sa x difference in concentration/diffusion distance
what will increase or decrease the rate of diffusion in ficks law
a or concentration
diffusion distance
name two types of molecules that use facilitated diffusion
charged and polar
why is facilitated diffusion different to simple
occurs at a specific point where there is a specific protein
how does diffusion occur in protein channels
protein channels form a water-filled hydrophilic channel
only open when a specific ion is present
ions bind to protein which causes it to open on one side and close on the other
how does diffusion occur in carrier proteins
specific molecule binds to a specific protein
causes it to change shape
causes it to be released inside membrane
what is water potential(kilopascal)
measure of the pressure that water molecules exert on membranes as they move around and randomly hit it
what happens when you dissolve something in water
cauxses wate rmolecules to attach to the dissolved molecule and decrease the amount of free water
what is osmosis
net movement of water molecules from a high to a more negative water potential across a partially permeable using mainly aquaporin channels
whats the difference between hypertonic and hypotonic
hypertonic - water leaves cell
hypotonic - water enters cell
What is the solution that plant cells bathes in
pure water
what happens in a hypotonic lant cell
water enters and causes protoplast to swell and push against the wall
what does being in full plasmolysis mean(hypertonic)
protoplast has pulled away from cell wall so much it causes it to shrink
what does being in incipient plasmolysis mean(isontic)
when the protoplast no longer presses on the wall
Name the 5 stages of transport in the illium
