Diffusion Flashcards
What is diffusion?
The movement of particles from an area of high concentration to an area of low concentration across a semi permeable membrane until equilibrium is reached
Is diffusion active or passive?
Passive
What factors affect the rate of diffusion?
The concentration gradient
Thickness of the exchange surface
The surface area
How does the concentration gradient affect the rate of diffusion?
The steeper the gradient, the faster the rate of diffusion
How does the thickness of the exchange surface affect the rate of diffusion?
The thinner the surface, the shorter the pathway and therefore the faster the rate of diffusion
How does surface area affect the rate of diffusion?
Larger the surface area, the faster the rate of diffusion
What is facilitated diffusion?
The movement of large or charged particles from an area of high concentration to an area of low concentration through a channel or carrier protein
Is facilitated diffusion active or passive?
Passive
What two types of proteins are involved in facilitated diffusion?
Channel
Carrier
What do carrier proteins move through the membrane?
Large molecules
How do carrier proteins work?
They have a binding site which the molecules binds to
It changes its shape
Opens up to release the molecule on the other side
What are channel proteins?
Pores in the membrane
What do channel proteins move through the membrane?
Charged particles
What two factors affect the rate of facilitated diffusion?
Concentration gradient
The number of channel and carrier proteins
How does the amount of channel and carrier proteins affect the rate of facilitated diffusion?
Once all of the proteins are in use, facilitated diffusion will slow until there’s one free to use
