Diffusion

• Diffusion is the net movement of particles from an area of high concentration to an area of low concentration. Dissolved substances and gases can move in and out cells, across the cell membrane, by diffusion.
• What substances does a cell need?

  Cells need to take in substances such as glucose and oxygen for respiration.
• What waste products does a cell need to get rid of?

  • They also need to get rid of waste products and chemicals that are needed elsewhere in your body
• Surface Area to Volume Ratio

  • The speed of diffusion remains constant.
  • However, the HCl can only enter the cube through its surface, so as that ratio decreases, the time it takes for diffusion to occur throughout the whole volume increases significantly.