diffusion

• What is diffusion?

  The spreading out of particles
• What does the term "net movement" in diffusion mean?

  Overall movement from high to low concentration
• Which three molecules move in and out of cells by diffusion?

  Oxygen, carbon dioxide, and urea
• Why do cells need oxygen?

  For respiration to generate energy
• How does the concentration of oxygen outside the cell compare to inside?

  Higher concentration outside than inside
• What happens to oxygen molecules during diffusion?

  They move from high to low concentration
• What is produced as a waste gas during respiration?

  Carbon dioxide
• How does the concentration of carbon dioxide inside the cell compare to outside?

  Higher concentration inside than outside
• What happens to carbon dioxide during diffusion?

  It moves out of the cell
• What is urea in relation to cells?

  A waste product produced inside cells
• How does urea exit the cells?

  By diffusion into the blood plasma
• What are the three main factors that affect the rate of diffusion?

  Concentration difference, temperature, surface area
• What is the concentration gradient?

  The difference in concentration across a space
• How does a greater concentration gradient affect diffusion?

  It increases the rate of diffusion
• How does temperature affect the rate of diffusion?

  Higher temperature increases the rate of diffusion
• Why does higher temperature increase diffusion rate?

  Particles have more kinetic energy and move faster
• How does surface area of the membrane affect diffusion?

  Larger surface area increases the rate of diffusion
• How does the surface area of two cells compare in terms of diffusion rate?

  The cell with larger surface area diffuses faster
• What are the factors affecting the rate of diffusion?

  • Difference in concentrations (concentration gradient)
  • Temperature
  • Surface area of the membrane
• What are the examples of molecules that diffuse in and out of cells?

  • Oxygen
  • Carbon dioxide
  • Urea
• What is the process of diffusion in cells?

  1. Molecules move from high concentration to low concentration
  2. Oxygen enters cells for respiration
  3. Carbon dioxide and urea exit cells as waste