ATS GCSE Biology - Plant organ system

• counting stomata

  1. use nail varnish to cover an area of the leaf2. peel from leaf3. place on microscope slide4. count the number of stomata in a random sample of squares5. calculate the mean number of stomata on a given area of a leaf6. use this number to estimate the number of stomata on the whole leaf

  
• plant organ system

  roots stem leaves for transport

  
• storage of sugars

  starch fats oils

  
• respiration


  immediate use of sugars

  
• companion cells


  support cells and help to keep phloem cells alive contain mitochondria to transfer energy to move dissolved food by active transport

  
• sieve plates


  pores in end walls between phloem cells allow cell sap to move freely

  
• phloem cell adaptations

  sieve plates living cells which lose a lot of their internal structures companion cells elongated cells
• phloem cells


  transports dissolved sugars from leaves to rest of plant moving sugars up and down around the plant for immediate use or storage

  
• mature xylem cells


  are dead

  
• xylem adaptations

  spirals of lignin support plant they are very strong

  
• xylem cells


  hollow tubes alive when first formed lignin builds in spirals in cell walls then the cells die to form long hollow tubes transports water and mineral ions in one direction from roots to leaves only

  
• root hair cell function

  take in water through osmosis and mineral ions by active transport

  
• close to xylem tissue

  short diffusion path

  
• many mitochondria

  to supply energy needed for active transport from respiration for transport of mineral ions

  
• large permanent vacuole


  speeds up movement of water and ionsmaintains concentration gradient

  
• large surface area

  for water & ions to move into root hair cell

  
• root hair cell adaptations

  large surface arealarge permanent vacuolemany mitochondriaclose to xylem tissue