BIOLOGY

• Human intestine


  • Surface covered in many villi
• Villi in human intestine

  • Have a large surface area
• The human intestine has a good blood supply to maintain the concentration gradient for diffusion
• The human intestine has a short diffusion pathway
• Alveoli in lungs


  • Have millions of villi which increase the surface area
• The alveoli in lungs have a short diffusion pathway
• The alveoli in lungs have a good blood supply
• Gills in fish


  • Have lots of gill filaments which increase the surface area
• The gills in fish have a thin membrane
• The gills in fish have a good blood supply
• The gills in fish have a short diffusion pathway
• Root hair cells


  • Increase the surface area to absorb water and minerals from the soil
• Leaves


  • Contain chlorophyll to absorb sunlight for photosynthesis
• Leaves have xylem and phloem to transport minerals and glucose through the plant
• Leaves


  • Have a large surface area to absorb light
• Stomata on leaves


  • Allow gases to diffuse into and out of the leaf