DIFFUSION, FACILITATED DIFFUSION AND OSMOSIS Flashcards
main characteristic of cell membranes
they are partially permeable
what does partially permeable mean? (provide examples of substances)
this means that smaller non-polar substances can travel through such as water and carbon dioxide
but bigger molecules such as glucose need ATP and proteins to pass through the Bilayer
3 methods by which substances can cross the membrane
Diffusion
Osmosis
Active Transport
what is diffusion?
the net movement of particles from a high concentration to a low concentration
2 characteristics of diffusion
a passive process that doesn’t require ATP, only kinetic
only occurs in liquids and gases (where particles move)
define concentration gradient
where a substance moves from a high concentration area to a low concentration area (balances composition)
what is an equilibrium?
a no net movement of particles in any direction
almost stagnant
what is facilitated diffusion?
this is the diffusion of larger water-soluble molecules through transport proteins
what is osmosis
the net movement of water molecules from a region of higher water potential to a region of low water potential through a partially permeable membrane
define facilitate
make an action or process easier
what potential does a low concentrated solution have
a HIGHER water potential
what potential does a high concentrated solution have
a LOWER water potential
what is the purpose of diffusion?
to reach an equilibrium
