Diffusion And Osmosis Flashcards
What happens in diffusion
Molecules move around randomly- kinetic energy
When there is equal conc of molecules there is no net change
Diffusion
Molecules moving from an area of high conc to an area of low conc until an equilibrium is reached
How does the concentration gradient affect the rate of diffusion
The steeper the concentration gradient the faster the rate of diffusion
How does the diffusion distance affect the rate of diffusion
The shorter the diffusion distance the faster the rate of diffusion
How does the surface area affect the rate of diffusion
The greater the SA the faster the rate of diffusion
How does the temperature affect the rate of diffusion
The close the temp, the slower the rate of diffusion & vice versa as molecules have more/ less kinetic energy
What is SA/ V ratio
The amount of SA per unit of volume
What are cell membranes….
Selectively permeable
What happens in diffusion when there is a large SA
Lose heat
Get rid of CO2 fast
Take up useful molecules
What happens in diffusion with a small SA
Retain heat well
What are the disadvantages of bigger organisms
The amount of SA it has per unit of volume gets smaller
Diffusion takes longer
The SA is too small for their volume
Osmosis
The movement of water molecules from an area of high water conc to an area of low water conc across a
Selectively permeable membrane
Solute concentration in cells
High water conc outside the cell diffuses into the cell
Cytoplasm
Water, salts, organic molecules
Vacuole
Contains cell sap (water amino acids salt water)
