B3 cont

• What is the focus of the video discussed in the study material?

  Gas exchange in plants
• What are the small openings on the underside of leaves called?

  Stomata
• What is one consequence of having stomata open in plants?

  The plant will experience water loss
• Why are stomata important for plants?

  They allow for gas exchange
• What is the upper protective layer of the leaf called?

  Upper epidermis
• What is the function of the waxy cuticle on the upper epidermis?

  To prevent excess water loss
• What is the name of the tightly packed cells in the leaf where photosynthesis occurs?

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

  To absorb sunlight effectively
• What is the area in the middle of the leaf called that is adapted for gas exchange?

  Spongy mesophyll
• How do gases move in and out of the leaf?

  Through the stomata and spaces in the spongy mesophyll
• What is transpiration?

  The loss of water vapor from the leaves
• How does water loss occur in plants?

  Water moves from moist areas to dry areas through stomata
• What factors can affect the rate of transpiration?

  Temperature and humidity
• How does temperature influence transpiration?

  Higher temperatures increase the rate of evaporation
• What happens to transpiration in humid conditions?

  It decreases due to smaller differences in water vapor content
• What are guard cells?

  Structures that control the opening and closing of stomata
• How do guard cells regulate stomatal opening?

  By swelling with water or collapsing when water is removed
• Why is it important for stomata to remain open?

  To allow carbon dioxide in for photosynthesis
• What is the purpose of a potometer in plant studies?

  • Measures transpiration rates
  • Simulates xylem water movement
  • Uses an air bubble to track water loss
• How can you calculate the volume of water transpired using a potometer?

  By measuring the distance the air bubble moves and multiplying by the tube's surface area
• What is stomatal density?

  The number of stomata in a given area
• How can stomatal density be investigated?

  By peeling the lower epidermis or using clear nail polish to make a cast
• What variables can be investigated regarding stomatal density?

  Different species of plants or plants in different environments
• What adaptations do plants have for gas exchange?

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