C1:cell biology and transport

• What is the definition of diffusion?

  The spreading out of particles from an area of higher concentration to an area of lower concentration.
• What factors affect the rate of diffusion?

  Difference in concentration, temperature, and surface area of the membrane.
• What is the direction of particle movement during diffusion?

  From an area of high concentration to an area of low concentration.
• Is energy required for diffusion?

  No, diffusion is a passive process.
• Give an example of diffusion in humans.

  Nutrients in the small intestine diffuse into the capillaries through the villi.
• How does oxygen diffuse in humans?

  Oxygen diffuses from the air in the alveoli into the blood in the capillaries.
• What happens to carbon dioxide in the human body?

  Carbon dioxide diffuses from the blood in the capillaries into the air in the alveoli.
• How does urea diffuse in the human body?


  Urea diffuses from cells into the blood for excretion in the kidney.
• How does diffusion occur in fish?

  Oxygen from water passing over the gills diffuses into the blood in the gill filaments.
• What happens to carbon dioxide in fish?

  Carbon dioxide diffuses from the blood in the gill filaments into the water.
• How does diffusion occur in plants?

  Carbon dioxide used for photosynthesis diffuses into leaves through the stomata.
• What happens to oxygen produced during photosynthesis in plants?

  Oxygen produced during photosynthesis diffuses out of the leaves through the stomata.
• What is osmosis?

  The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.
• In which direction does water move during osmosis?

  From an area of lower solute concentration to an area of higher solute concentration.
• Is energy required for osmosis?

  No, osmosis is a passive process.
• How does water move by osmosis in plants?

  Water moves from a dilute solution in the soil to a concentrated solution in the root hair cell.
• What is active transport?

  The movement of particles from a more dilute solution to a more concentrated solution using energy from respiration.
• What is required for active transport?

  Energy released by respiration is required.
• In which direction do particles move during active transport?

  From an area of low concentration to an area of high concentration.
• How does active transport function in humans?

  Active transport allows sugar molecules to be absorbed from the small intestine when the sugar concentration is higher in the blood than in the small intestine.
• How does active transport function in plants?

  Active transport is used to absorb mineral ions into the root hair cells from more dilute solutions in the soil.
• What are some key terms related to cell transport processes?

  • Concentration
  • Membrane
  • Cell wall
  • Chloroplast
  • Chromosome
  • Cytoplasm
  • Dilute
  • DNA
  • Eukaryotic
  • Gradient
  • Magnification
  • Mitochondria
  • Passive process
  • Partially permeable membrane
  • Plasmid
  • Prokaryote
  • Resolution
  • Ribosome
  • Root hair cell
  • Stomata