Leaf Structure

• Photosynthesis


  A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic.
• Factors affecting photosynthesis

  • Temperature
  • Carbon dioxide concentration
  • Light intensity
• Green plants and algae use light energy to make glucose and oxygen from carbon dioxide and water
• Organ


  A group of different tissues that work together to carry out a particular function, eg heart and lungs.
• Plant structure

  • Leaves
  • Stems
  • Roots
• Leaf structure

  • Large surface area
  • Thin
  • Chlorophyll
  • Network of veins
  • Stomata
• Adaption


  A change or the process of change by which an organism or species becomes better suited to its environment.
• Large surface area of leaves


  Absorb more light
• Thin leaves


  Short distance for carbon dioxide to diffuse into leaf cells
• Chlorophyll in leaves

  Absorbs sunlight to transfer energy into chemicals
• Network of veins in leaves

  Support the leaf and transport water and sugars
• Stomata in leaves

  Allow carbon dioxide to diffuse into the leaf and oxygen to diffuse out
• Internal leaf structure

  • Thin, transparent epidermis
  • Thin cuticle of wax
  • Palisade cell layer
  • Spongy layer with air spaces
  • Palisade cells with many chloroplasts
• Thin, transparent epidermis


  Allow more light to reach the palisade cells
• Thin cuticle of wax

  Protect the leaf from infection and prevent water loss without blocking out light
• Palisade cell layer at top of leaf

  Absorb more light and increase the rate of photosynthesis
• Spongy layer with air spaces


  Allow carbon dioxide to diffuse through the leaf
• Palisade cells with many chloroplasts

  Absorb all the available light
• what is the vascular bundle?


  xylem transports water and mineral ions and phloem transports amino acids and sucrose