Plant cell

• Lignin:

  A substance that strengthens the cell walls of xylem cells in plants.
• How are root hair cells adapted to it's functions:

  • No chloroplasts - they are underground so sunlight can't reach them for photosynthesis.
  • Long projections - Increase the surface area that the plant can use to absorb water and minereals.
• Xylem cell adaption:

  • Lignin - strengthens cell walls
  • Broken end walls - allows water movements
• Xylem transport water and minereals through the transpiration stream.
• Phloem transports sucrose and amino acids through the process of translocation.
• Leaves are adapted for exchanging oxygen and carbon dioxide between the leaves and the surrounding air.
• Why is stomta located in upper epidermal layer and not lower epidermal layer:

  So the stomata isn't blocked by water and gas exchange will occur.