2.17 - Plant Cell Organisation

• What are the levels of organisation in plants?

  Cells

  Tissues

  Organs

  Organ Systems
• What structures help plants minimise water loss?

  Guard cells which can close stomata

  Waxy cuticle
• What is the function of the waxy cuticle on leaves?

  It helps reduce water loss
• What happens to guard cells when there is plenty of water in the leaf?

  • Guard cells become turgid
  • Stomata open
  • Allows carbon dioxide to enter
  • Allows water to escape
• What is the state of guard cells when they are flaccid?

  They are not turgid and stomata close
• What is the effect of stomata opening on gas exchange?

  It allows carbon dioxide to enter the leaf
• What is a consequence of stomata opening for water in the leaf?

  Water escapes from the leaf
• How do guard cells regulate the opening and closing of stomata?

  By becoming turgid or flaccid based on water availability
• At nighttime, when photosynthesis can’t take place, are the stata open or closed?


  Closed
• What is meristem tissue and where is it found?

  Stem cells

  Tips of shoots and roots