Diffusion

• The rate of diffusion depends on temperature, surface area, and concentration gradient.
• Diffusion is the movement of particles from an area of high concentration to low concentration.
• Diffusion is the spreading out of the particles of a gas, or any substance in solution (a solute). This results in the net movement (overall movement) of particles.
• Diffusion occurs from an area of high concentration to low concentration until equilibrium is reached.
• The rate of diffusion is affected by the concentration gradient, temperature, surface area to volume ratio, and pressure.
• Particles move randomly but there are more collisions with other particles at higher concentrations so they tend to diffuse away from areas of high concentration
• A larger surface area means more particles will have a chance to escape into the air
• Increasing the surface area increases the number of particles that can be involved in diffusion
• Concentration gradient - The greater the difference between the concentrations at either end of the pathway, the faster the rate of diffusion will be.
• Temperature - As temperature increases, the kinetic energy of the particles also increases, causing them to move more rapidly. Therefore, they collide with other particles more frequently, increasing the frequency of successful collisions that result in diffusion.
• Surface Area to Volume Ratio - A larger surface area means there are more opportunities for molecules to diffuse into/out of the cell.
• Decreasing the volume decreases the distance that particles have to travel which speeds up diffusion
• Increasing the surface area increases the number of particles that can be involved in diffusion as it provides more opportunities for particles to escape from one side and enter another
• Increasing the temperature increases the kinetic energy of the particles which makes them move faster and therefore increase the rate of diffusion
• Temperature affects the speed of particle movements - faster temperatures mean faster diffusion rates
• Diffusion


  The net movement of particles from an area of higher concentration to an area of lower concentration
• Diffusion


  1. Molecules move about randomly

  2. Molecules spread out over time

  3. Molecules become evenly distributed
• Diffusion can happen in both gases and liquids
• Partially permeable membrane


  Only some molecules can diffuse through, like water, glucose, and amino acids, while larger molecules like proteins and starch cannot
• Diffusion is a passive process that does not require energy from the cell
• Factors affecting rate of diffusion

  • Concentration gradient
  • Temperature
  • Surface area
• Larger concentration gradient


  Higher rate of diffusion
• Higher temperature


  Higher rate of diffusion
• Larger surface area


  Higher rate of diffusion