Diffusion: Oak National Academy Flashcards
What is diffusion?
- Diffusion is the spreading out of particles which leads to the net movement of particles from an area of high to low concentration.
What is meant by “concentration?”
Concentration is the mass of solute dissolved per unit volume of solvent.
Does diffusion require energy?
Diffusion is a passive process that doesn’t require any energy.
Does diffusion stop?
Diffusion doesn’t stop. When the substances reach the same concentration, particles move randomly.
There is simply no NET movement
What 4 factors affect the rate of diffusion?
1.) Temperature.
2.) Difference in concentration (concentration gradient)
3.) Surface area of membrane
4.) Diffusion distance
Why does increased temperature increase the rate of diffusion?
The particles have more kinetic energy to move faster.
Why does increased surface area increase the rate of diffusion?
Because there is more contact between surafces and the particles that are going to diffuse in.
What does the concentration gradient show?
The concentration gradient shows the difference in concentration.
Suggest why cell membranes are very thin.
- This decreases the diffusion distance so particles can move quicker, increasing the rate of diffusion.
Suggest why all cells have foldings for exchange of materials.
- All cells have foldings to increase the surface area so there is more contact, increasing the rate of diffusion.
Give 3 substances that diffuse in and out of cells.
- oxygen
- carbon dioxide
- urea
What happens to urea after it diffuses out of a cell?
- It is carried by plasma and excreted by kidneys.
Give 4 features that make an exchange surface more effective.
- Large surface area
- Thin membrane
- Good blood supply
- Being ventilated (gas exchange)
True or False. Diffusion can occur in all states.
- False. Occurs in liquids and gases.
Why is diffusion important?
- Products from cell processes removed
- To take in substances for use in cell procesess.
