Diffusion Flashcards
(9 cards)
What is diffusion
Net movement of particles from an area of higher concentration to an area of lower concentration.
Molecules diffuse both ways but the net movement will be to the lower concentration. This continues to particles are evenly distributed throughout the liquid or gas. Particles diffuse down the concentration gradient
What is the process of diffuse and what can pass through
It is passive so no energy is requires for it to happen when molecules diffuse directly through the cell membrane it is known as simple diffusion
Oxygen and carbon dioxide can pass as they are small as well as they are non polar
What are the factors that can affect the rate of diffusion and explain
The concentration gradient - the higher it is the faster it is, diffusion slows down over time
The thickness of the exchange surface - the thinner the exchange surface, the shorter the distance the particles have to travel so the faster diffusion is
The surface area - the larger the surface area the faster the rate of diffusion
How do larger molecules diffuse through the cell membrane
Facilitated diffusion
What is facilitated diffusion
This is when large/charged particles diffuse through channel and carrier proteins in the cell membrane, it still moves particles down a concentration gradient from a higher to lower concentration. It is also a passive process so it doesn’t use energy
Tell me about carrier proteins
Move large molecules across the membrane down the concentration gradient
A large molecule attaches to the carrier protein in the membrane
Then the proteins changes shape
This releases the molecule of the opposite side of the membrane
Tell me about channel proteins
They form pores in the membrane for charged particles to diffuse through
What factors effect the rate of facilitated diffusion and explain
The concentration gradient - the higher the concentration gradient the faster the rate of diffusion is, it slows down after time
The number of channel and carrier proteins - once all the proteins are in use you can’t make facilitated diffusion happen any faster even if you increase the concentration gradient
How do you calculate the rate of diffusion
Find the gradient, might include drawing an tangent change in y/change in x
