Plant tissues and organs

• What is the function of epidermal tissue in plants?

  It covers the surface of the leaf and provides protection.
• How does epidermal tissue adapt to its function?

  It secretes a waxy substance that waterproofs the surface of the leaf.
• What is the main site of photosynthesis in plants?

  Palisade mesophyll.
• What adaptation does palisade mesophyll have for photosynthesis?

  It contains lots of chloroplasts.
• What is the function of spongy mesophyll in plants?

  It carries out some photosynthesis and allows the diffusion of gases.
• How is spongy mesophyll adapted for gas diffusion?

  It contains some chloroplasts, has large air spaces, and a large surface area to make diffusion easier.
• What is the primary function of xylem in plants?

  It carries water and dissolved minerals from the roots to the leaves.
• What adaptations does xylem have to withstand water pressure?

  It has spirals and rings of lignin which make the tissue very strong.
• What is the function of phloem in plants?

  It carries dissolved glucose/sugars from leaves to the rest of the plant.
• How do phloem cells facilitate the movement of substances?

  Cells join together to form long hollow tubes that allow water and mineral ions to move easily through them.
• What are the key characteristics of xylem and phloem?

  • Xylem:
  • Companion cells
  • Hollow
  • Lignin
  • Dead cells
  • Unidirectional
  • Phloem:
  • Companion cells
  • No lignin
  • Living cells
  • Bidirectional
  • Both tubular
• What is the function of root hairs in plants?

  They store water, minerals, and provide anchorage.
• What is transpiration in plants?

  It is the process by which water is lost by evaporation through the stomata.
• When do stomata typically open and close?

  Stomata open in the day and close at night to keep water inside.
• What factors can increase transpiration in plants?

  • Temperature
  • Windiness
  • Humidity
  • Light
• What is the chemical equation associated with photosynthesis?


  CO₂ + H₂O.
• What role does the upper epidermis play in plants?

  It protects the leaf and helps prevent water loss.
• How do xylem and phloem differ in terms of cell structure and function?

  Xylem consists of dead cells and transports water unidirectionally, while phloem consists of living cells and transports sugars bidirectionally.
• How does the structure of xylem contribute to its function in water transport?

  The hollow structure and lignin provide strength to withstand water pressure.
• What adaptations of palisade mesophyll enhance its role in photosynthesis?

  Its high concentration of chloroplasts maximizes light absorption for photosynthesis.