Diffusion Flashcards
what is the definition of diffusion?
the net movement of particles from a region of high concentration to a region of low concentration, due to the random movement of particles
when will diffusion stop?
when the equilibrium is reached
can solids diffuse by simple diffusion?
no only liquids and gases
why can liquids and gases diffuse through simple diffusion?
because their molecules possess kinetic energy and move randomly
are water molecules polar or non-polar?
polar
are water molecules lipid soluble or insoluble?
insoluble
why would you think that water cannot diffuse through the lipid bilayer?
because it polar and lipid insoluble
when can water sometimes directly diffuse?
if there is high levels of water molecules
how can water molecules diffuse?
some membranes use aquaporin channels to allow water to move across the membrane
what are aquaporin?
special water channel proteins that allow water to move across the membrane
where are the 2 places facilitated diffusion takes place?
through channel proteins and through carrier proteins
what size molecules go through channel proteins?
small
what size molecules go through carrier proteins?
large
what molecules go through channel proteins and why?
small molecules that have polarity cannot pass through because of the hydrophobic tails
how do molecules go through channel proteins?
they pass through water-filled protein channels down a concentration gradient and do not require energy
way to remember channel proteins
eurotunnel
what molecules go through carrier proteins and why?
larger molecules that are too big to pass through channel proteins and tf require a carrier protein
how do molecules diffuse through using carrier proteins?
carrier proteins bind with specific molecules, which opens the protein to allow the molecules to cross the membrane
what is special about carrier proteins?
they have a specific shape, normally carrying only one specific shaped molecule
what are 5 factors that affect diffusion?
-temperature
-diffusion distance
-surface area
-size and type of diffusing molecule
-concentration gradient
summary of diffusion
simple diffusion:
-small molecules
-gases and liquids
-lipid soluble molecules
facilitated diffusion:
-channel proteins
smaller
-carrier proteins
bigger
way to remember carrier protein
carry, heavy bigger things
explain how temperature affects the rate of diffusion
-as temperature increases, molecules will have more kinetic energy and move faster tf rate of diffusion will increase
-as they lose heat energy, this will slow down the rate of diffusion
explain how diffusion distance affects the rate of diffusion
the thinner the membrane, the shorter the diffusion distance tf the rate of diffusion is increased
