Plants

• What do plants need to exchange for respiration and photosynthesis?

  Gases
• What is the main gas exchange surface in plants?

  The leaf
• How is the structure of a leaf related to its function?

  It is designed for efficient gas exchange
• What is the leaf blade also known as?

  Lamina
• Why is the leaf blade thin and flat?

  To provide a large surface area
• What do short diffusion pathways for gases facilitate?

  Efficient gas exchange
• What are the main parts of a flowering plant's leaf that you need to label?

  • Waxy cuticle
  • Upper epidermis
  • Palisade mesophyll
  • Spongy mesophyll
  • Vascular bundle
  • Stomata
  • Guard cell
• What are the functions of the leaf structures?

  • Waxy cuticle: Reduces water loss
  • Upper epidermis: Allows light passage
  • Palisade mesophyll: Main photosynthetic tissue
  • Spongy mesophyll: Gas circulation
  • Vascular bundles: Transport water and nutrients
  • Guard cells: Control stomatal opening
  • Stomata: Allow gas exchange
• What is the function of the waxy cuticle?

  Reduces water loss from the leaf
• What is the role of the upper epidermis in leaves?

  Allows light to pass to mesophyll
• What is the main function of the palisade mesophyll?

  Photosynthesis
• How do spongy mesophyll cells contribute to photosynthesis?

  They contain chloroplasts for photosynthesis
• What do vascular bundles contain?

  Xylem and phloem
• How do guard cells function in gas exchange?

  They open and close the stomatal pore
• What do stomata allow in plants?

  Gaseous exchange
• What adaptations do leaves have for gaseous exchange?

  • Spongy mesophyll allows gas circulation
  • Air spaces permeate plant tissues
  • Stomatal pores facilitate gas entry and exit
  • Gases diffuse through stomata down a gradient
  • Gases diffuse through intercellular spaces
  • Gases dissolve in moisture covering cells
• What adaptations do leaves have for photosynthesis?

  • Large surface area for light capture
  • Orientation for maximum light exposure
  • Thin structure for light penetration
  • Transparent cuticle and epidermis
  • Elongated palisade mesophyll cells
  • Chloroplasts arranged for optimal light absorption
• How do chloroplasts adapt for light absorption?

  They can rotate and move within cells
• What are stomata?

  Pores for gas exchange
• What is the role of guard cells in relation to stomata?

  They control the opening and closing
• What happens to guard cells when they swell?

  They open the stomatal pore
• What causes guard cells to become flaccid?

  Water leaves the guard cells
• What is the process of stomatal opening during the day?

  1. Potassium ions are pumped into guard cells
  2. Starch converts to malate
  3. Water potential lowers
  4. Water enters by osmosis
  5. Guard cells become turgid
  6. Stomatal pore opens
• What is the process of stomatal closing when light is low?

  1. Potassium ions diffuse out of guard cells
  2. Malate converts back to starch
  3. Water potential increases
  4. Water leaves by osmosis
  5. Guard cells become flaccid
  6. Stomatal pore closes
• What is the effect of low light intensity on guard cells?

  They become flaccid and close stomata
• How does the structure of guard cells facilitate their function?

  Thick inner walls cause curvature when turgid