Diffusion

• What is diffusion?

  Movement of particles from high to low concentration
• What is the key characteristic of diffusion?

  It is a passive process that does not require energy
• In which states of matter does diffusion occur?

  In liquids and gases, not solids
• How does concentration difference affect diffusion speed?

  Bigger difference leads to faster diffusion
• What is the definition of diffusion?

  Net movement from high to low concentration until equilibrium
• How does oxygen and carbon dioxide diffuse in gas exchange?

  Oxygen diffuses into blood; CO₂ diffuses out
• How do glucose and amino acids diffuse in the small intestine?

  They diffuse into the blood through intestinal walls
• How does urea diffuse in excretion?

  Urea diffuses out of cells into the blood
• How does the smell of perfume spread in a room?

  Perfume molecules move from high to low concentration
• What factors affect diffusion?

  • Concentration Gradient
  • Temperature
  • Surface Area
  • Membrane Thickness
  • Distance
• How does the concentration gradient affect diffusion?

  Bigger difference results in faster diffusion
• How does temperature affect diffusion?

  Higher temperature increases particle movement speed
• How does surface area affect diffusion?

  Larger surface area leads to faster diffusion
• How does membrane thickness affect diffusion?

  Thinner membrane results in faster diffusion
• How does distance affect diffusion?

  Shorter distance leads to faster diffusion
• Why are alveoli and villi adapted for diffusion?

  • Large surface area for more diffusion
  • Thin walls for shorter diffusion distance
  • Good blood supply to maintain concentration gradient
• What is the aim of the required practical investigating diffusion in agar jelly?

  • Investigate how size affects diffusion rate
• What equipment is needed for the diffusion practical?

  • Agar jelly with indicator
  • Hydrochloric acid
  • Ruler
  • Stopwatch
• What is the method for investigating diffusion in agar jelly?

  1. Cut different-sized agar cubes
  2. Place in hydrochloric acid
  3. Time color disappearance
  4. Compare results for sizes
• What are the expected results of the diffusion practical?

  Smaller cubes diffuse faster than larger cubes
• What are the differences between diffusion, osmosis, and active transport?

  • Diffusion: Particles move high to low concentration
  • Osmosis: Water molecules move high to low concentration
  • Active Transport: Particles move low to high concentration
• What moves during diffusion?

  Particles like gases and small molecules
• What moves during osmosis?

  Water molecules
• What moves during active transport?

  Particles like ions and glucose
• What direction does diffusion move particles?

  From high to low concentration
• What direction does osmosis move water molecules?

  From high to low concentration
• What direction does active transport move particles?

  From low to high concentration
• Does diffusion require a membrane?

  No, but can happen across one
• Does osmosis require a membrane?

  Yes, it requires a partially permeable membrane
• Does active transport require energy?

  Yes, it requires energy from ATP
• What are key terms related to diffusion?

  • Diffusion: Movement from high to low concentration
  • Concentration Gradient: Difference in concentration
  • Equilibrium: Equal concentration throughout
  • Passive Transport: No energy required
  • Partially Permeable Membrane: Allows some substances through