Rate of diffusio Flashcards
3 factors affecting the rate of diffusion
- surface area
- diffusion distance
- concentration gradient/difference
surface area and rate of diffusion
effectiveness of an exchange surface increases with:
- increase in surface area
- e.g. alveoli in lungs
explanation of surface area
- particles pass through membranes in organisms
- if the SA of the membrane is increased, more particles can pass through as there is more space
- increases the overall rate of diffusion
diffusion distance and rate of diffusion
effectiveness of an exchange surface increases with:
- a shorter distance for diffusion
- e.g. surfaces are one cell thick
explanation of diffusion distance
- the further the particles have to diffuse, the slower the rate of diffusion
- increasing thickness of a membrane decreases the rate of diffusion
concentration difference and rate of diffusion
effectiveness of an exchange surface increases with:
- the maintenance of a high concentration gradient
- e.g. animals have an efficient blood supply
concentration gradient
the difference between two concentrations
equation for concentration
mass of solute (g) / volume of solution (dm[3])
explanation for concentration difference
-diffusion is faster if there is a big difference in the concentrations
- between the area the substance travels from
- and the area that is is moving to
factors affecting diffusion and proportion
- rate of diffusion (is directly propotional to) the surface area and/or the concentration difference
- rate of diffusion (is inversely proportional to) the thickness of the membrane
(shown as 1/membrane thickness)
Fick’s law
describes the relationship between the rate of diffusion and three factors that affect diffusion
the rate of diffusion is directly proportional to:
(surface area x concentration difference) / thickness of membrane
What is Fick’s law used for?
calculating the rate of diffusion
