diffusion

• What is diffusion?

  Diffusion is the spreading out of particles resulting in a net movement from an area of higher concentration to an area of lower concentration.
• What does the term "net" mean in the context of diffusion?

  "Net" refers to the overall movement of particles during diffusion.
• Which three molecules move in and out of cells by diffusion?

  • Oxygen
  • Carbon dioxide
  • Urea
• Why do cells need oxygen?

  Cells need oxygen for respiration, which is carried out by mitochondria.
• What happens to oxygen molecules when there is a higher concentration outside the cell than inside?

  The oxygen molecules move into the cell by diffusion.
• What is the concentration of carbon dioxide inside the cell compared to outside?

  The concentration of carbon dioxide is higher inside the cell than outside.
• How does carbon dioxide move out of the cell?

  Carbon dioxide moves out of the cell by diffusion.
• What is urea and how does it move out of cells?

  Urea is a waste product produced inside cells that diffuses out into the blood plasma.
• What are the three main factors that affect the rate of diffusion?

  1. Difference in concentrations (concentration gradient)
  2. Temperature
  3. Surface area of the membrane
• What is the concentration gradient?

  The concentration gradient is the difference in concentration between two areas.
• How does a greater concentration gradient affect diffusion?

  A greater concentration gradient results in a faster rate of diffusion.
• How does temperature affect the rate of diffusion?

  The higher the temperature, the greater the rate of diffusion due to increased kinetic energy of particles.
• How does the surface area of the membrane influence diffusion?

  A larger surface area of the cell membrane increases the rate of diffusion.
• Which cell has a greater rate of diffusion: one with a larger surface area or one with a smaller surface area?

  The cell with a larger surface area has a greater rate of diffusion.
• What should you be able to describe by the end of the video on diffusion?

  • The meaning of diffusion
  • The factors that affect the rate of diffusion