Plant

• what are the plant tissues

  • epidermal
  • palisade mesophyll
  • spongey mesophyll
  • xylem and phloem
  • meristem
• what is the waxy cuticle

  • protective layer on the top of the leaves which prevents water from evapourating
• what is the upper epidermis

  • thin and transparent to allow light to enter palisade cells below
• what is the palisade mesophyll

  • contains chloroplasts which maximise photosytheisis by absorbing light
• what is the spongey mesophyll

  • contains internal air spaces which increase the SA:V ratio for the diffusion of CO2
• what is the lower epidermis

  • contains guard cells and stomata
• what are guard cells

  • abosrb and loose water to open and close the stomata to allow co2 to diffuse in and oxygen to diffuse out
• what are the stomata

  • where gas exchange occur
  • open during the day and closed during the night
  • also the site of evapouration of water
  • foudn on the underside of the leaf
• why are stomata found on the bottom of the leaf

  • to reduce water loss
• what is the vascular bundle

  • contains xylem and phloem to transport substances
• what is the xylem

  • transports water into the leaf for cells to use for photosynthesis
• what is the phloem

  • transports sucrose and amino acids
• what are the adaptations of a leaf

  • Large surface area - increases rate of diffusion and absorbtion of light
  • thin - allows CO2 to diffuse into palisade mesophyll cells quickly
  • chlorophyll - absorbs light energy so that photosyntheis
  • network of veins - allows the transport of water to the cells of the leaf and carbohydrates
  • stomata - allows CO2 to diffuse
• what is the function of xylem

  • transports water and minerals from the roots to the stem and leaves