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Diffusion - Coggle Diagram
Diffusion
Definition
net movement of molecules
(or ions) from region HIGH conc
to region LOW conc until evenly
spread out
Examples
diffusion oxygen alveoli -> blood
carbon dioxide blood -> alveoli
diffusion digested
food molecules
gut into blood
What Affects Rate
of Diffusion across
Membrane?
Difference in
Concentration
Greater distance,
faster rate
of diffusion
Thickness of
Exchange
Surface
quicker diffusion through
thinner membranes -
SHORTER DIFFUSION
PATHWAY
Surface
Area
Quicker if membrane
has larger SA
Size of
Molecules
small molecules
diffuse FASTER
Temperature
increase in temp.
increases rate of
diffusion - molecules
greater KINETIC
ENERGY
Fick's Law
(Surface Area
x
Difference in Conc)
÷
Thickness of Surface
Simple Diffusion
SMALL molecules pass
between phospholipid bilayer
non polar + lipid
soluble (hydrophobic)
substances
due to hydrophobic nature
of centre of phospholipid
bilayer
high to low conc. DOWN
concentration gradient
movement in BOTH directions
but NET movement H-->L