Gas Exchange in Plants

• What are the small openings on the underside of leaves called?

  Stomata
• What is the function of stomata in plants?

  Allow air to enter or exit
• What is a consequence of having stomata open?

  Water loss from the plant
• What is the role of the upper epidermis in leaves?

  Protects the leaf
• What covers the upper epidermis to prevent water loss?

  A waxy cuticle
• What is the tightly packed cell layer in leaves called?

  Palisade mesophyll
• Why are palisade mesophyll cells located at the upper surface of the leaf?

  To absorb sunlight effectively
• What is the spongy mesophyll adapted for?

  Gas exchange
• What gases do palisade mesophyll cells need for photosynthesis?

  Carbon dioxide and oxygen
• What is transpiration?

  Loss of water vapor from leaves
• How does water move through plants during transpiration?

  Evaporates through stomata
• What factors affect the rate of transpiration?

  Temperature and humidity
• How does temperature influence transpiration?

  Higher temperature increases transpiration
• What happens to transpiration in humid conditions?

  It decreases
• What are guard cells responsible for?

  Opening and closing stomata
• How do guard cells control stomatal opening?

  By swelling or collapsing with water
• Why is controlling stomatal opening important for plants?

  To regulate gas exchange and water loss
• What is a potometer used for?

  • Measures transpiration in plants
  • Simulates xylem water movement
  • Uses air bubble to track water loss
• What is stomatal density?

  Number of stomata per area
• How can stomatal density be investigated?

  By peeling epidermis or using nail polish
• What can be compared using stomatal density measurements?

  Different plant species or environments
• What adaptations do plants have for gas exchange?

  • Stomata for gas exchange
  • Guard cells for regulation
  • Palisade mesophyll for photosynthesis
  • Spongy mesophyll for air spaces