Leaf Structure and Function Quiz

Leaf Structure

• Cuticle:

  • Made of wax, waterproofing the leaf
  • Secreted by cells of the upper epidermis

• Upper Epidermis:

  • Thin and transparent, allowing light to pass through
  • Contains no chloroplasts
  • Acts as a barrier to disease organisms

• Palisade Mesophyll:

  • Main region for photosynthesis
  • Cells are column-shaped and densely packed with chloroplasts
  • Capture light energy
  • Receive carbon dioxide from air spaces from the spongy mesophyll

• Spongy Mesophyll:

  • Cells are more rounded and loosely packed
  • Contain chloroplasts, but fewer than palisade cells
  • Contain air spaces that allow for gas exchange (carbon dioxide in, oxygen out)

• Vascular Bundle:

  • A leaf vein made of xylem and phloem
  • Xylem transports water and minerals to the leaf
  • Phloem transports sugars and amino acids away

• Lower Epidermis:

  • Acts as a protective layer
  • Contains stomata (pores) for regulating water loss (transpiration) and gas exchange

• Stomata:

  • Each stoma is surrounded by a pair of guard cells
  • Guard cells control whether the stoma is open or closed
  • Water vapor passes out during transpiration
  • Carbon dioxide enters and oxygen exits during photosynthesis