Diffusion

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  • Created by: zoolouise
  • Created on: 19-04-16 16:50

Diffusion

  • Diffusion - the overall net movement of molecules or ions from a region where they're in high concentration to a region of lower concentration until they're equally distributed
  • The concentration gradient - the path from an area of higher concentration to an area of lower concentration, particles diffuse down a concentration gradient.

Diffusion is defined as the overall net movement of molecules or ions from a region where they are in high concentration to a region of low concentration until they are equally distributed.  Diffusion is an example of passive transport and the energy needed comes from the natural, inbuilt motion of particles rather than from an external source.

You need to understand that all particles are constanatly in motion due to the kinetic energy that they possess. This motion is random, with no set pattern to the way the particles move around. Particles are constantly bouncing off one another as well as off other objects. 

There are a number of factors which affect the rate at which molecules or ions diffuse:

  • Concentration gradient - the greater the difference in the concentration of molecules in two areas, the greater the rate of dissuion
  • The surface area of the membrane - the larger the area, the quicker the rate of diffusion
  • Thickness of the membrane - the thinner the membrane, the quicker the rate of diffusion
  • The distance of travel - the shorter the distance between two areas, teh greater the rate
  • An increase in temperature results in an increase in rate since there is an…

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