diffusion

• What is the definition of 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.
• How does the concentration of oxygen outside the cell compare to that inside the cell?

  The concentration of oxygen is higher outside the cell than inside the cell.
• What happens to oxygen molecules when they move into the cell?

  Oxygen molecules move from an area of higher concentration to an area of lower concentration by diffusion.
• What is produced as a waste gas during respiration?

  Carbon dioxide is produced as a waste gas during respiration.
• How does the concentration of carbon dioxide inside the cell compare to that outside?

  The concentration of carbon dioxide is higher inside the cell than outside.
• What happens to carbon dioxide molecules during diffusion?

  Carbon dioxide molecules move out of the cell from an area of higher concentration to an area of lower concentration.
• 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 is the first factor that affects the rate of diffusion?

  The difference in concentrations, known as the concentration gradient, affects the rate of diffusion.
• How does a greater concentration gradient affect diffusion?

  A greater concentration gradient results in a faster rate of diffusion.
• What is the second factor that affects the rate of diffusion?

  The second factor is temperature; higher temperatures increase the rate of diffusion.
• Why does a higher temperature increase the rate of diffusion?

  A higher temperature increases the kinetic energy of particles, causing them to move faster.
• What is the third factor that affects the rate of diffusion?

  The third factor is the surface area of the membrane; a larger surface area increases the rate of diffusion.
• How does the surface area of a cell membrane affect diffusion?

  A larger surface area of the cell membrane results in a greater rate of diffusion.
• 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