Movement Into An Out Of Cells Y9 Flashcards
Definition of diffusion
The random movement of particles from an area of high concentration to an area of low concentration until dynamic equilibrium is reached
Example of diffusion
Diffusion of oxygen into a cell- the concentration of oxygen molecules is greater outside the cell than inside. So the oxygen molecules diffuse into the cell
Factors that effect diffusion
1.increase in surface area
2.decreasing the diffusion pathway
3.increasing the concentration gradient
4.increasing the temperature
5.smaller the particles
Why does increasing the surface area affect diffusion
More surface area provides more space for particles to move across, allowing for more particles to diffuse at the same time.
Why does decreasing the diffusion pathway affects diffusion?
Particles have less far to move therefore they diffuse faster-it takes less time
Why does increasing the concentration gradient affect diffusion?
The difference in concentration between the two areas is bigger. The biggest difference is the faster diffusion happens.
Why does increasing the temperature affect diffusion?
When particles are hotter, they have more kinetic energy therefore be diffused faster. E.g making a cup of tea.
Why does making the particles smaller affect diffusion?
The particles are lighter so they move quicker. They are able to fit through the membrane more easily.
Definition of active transport
The random movement of particles from an area of low concentration to an area of high concentration using energy.
Active transport example
Plants need minerals from the soil for growth. The concentration of minerals in soil is lower then the concentration of minerals inside a root hair cell
How can particles move up the concentration gradient
If energy is used (like in active transport)
Definition of osmosis
The diffusion of water molecules from a dilute solution,(high water potential) to a concentrated solution,(low water potential) across a partially permeable membrane.
Water potential in a dilute solution
High water potential
Water potential in a concentrated solution
Low water potential
What is water potential
Ability of H2O molecules to move
Rule of Surface area and volume ratio
As objects get bigger their SA:V ratio gets smaller
How to work out SA:V ratio
Calculate SA of one side
Multiply by 6 (number of sides)
Calculate volume
Compare in a ratio
