plant organisation

• What do plants use to transport food, water, and minerals?

  Transport system
• What is the function of xylem in plants?

  Moves water and minerals from roots to leaves
• What does phloem transport in plants?

  Food substances like sucrose and amino acids
• What is the term for the movement of food in plants?

  Translocation
• How do xylem and phloem compare in structure?

  Xylem consists of dead cells; phloem has living cells
• How do root hair cells absorb water?

  By osmosis
• What is the role of mitochondria in root hair cells?

  Release energy for active transport
• What are the purposes of absorbed water in plants?

  Photosynthesis, support, cooling, and transport
• Where are stomata located in plants?

  Underside of leaves
• What do stomata control in plants?

  Water loss and gas exchange
• How do guard cells function in relation to stomata?

  They regulate the opening and closing of stomata
• What happens to guard cells in bright light?

  They take in water and become turgid
• What is the effect of low light on guard cells?

  They lose water and become flaccid
• Why do plants regulate stomatal size?

  To control transpiration and water loss
• What is the main function of xylem tissue?

  Transport water and minerals
• What is the composition of xylem cells?

  Dead cells that form hollow tubes
• What strengthens xylem cells?

  Lignin
• What type of process is transport in the xylem?

  Physical process that does not require energy
• What does phloem transport?

  Food substances produced by photosynthesis
• What is the direction of transport in phloem?

  Upwards and downwards
• What is the transport sugar in phloem?

  Sucrose
• What is required for translocation in phloem?

  Energy
• What are sieve tubes in phloem specialized for?

  Transport of substances
• What do companion cells provide for sieve tubes?

  Energy for transport
• What is the relationship between sieve tubes and companion cells?

  Sieve tubes depend on companion cells
• What is transpiration in plants?

  • Evaporation of water from leaf surfaces
  • Water loss through open stomata
  • Draws water from xylem to replace lost water
• What is the transpiration stream?

  Water pulled up the stem by evaporation
• What is the role of cohesion in transpiration?

  Water molecules attract each other
• What percentage of water taken up by plants is used for photosynthesis?

  5%
• What are root hairs adapted for?

  Absorbing water and minerals
• How do minerals enter root hair cells?

  By active transport
• What factors affect the rate of transpiration?

  • Temperature
  • Humidity
  • Air movement
  • Light intensity
• How does temperature affect transpiration rate?

  Increased temperature raises evaporation rate
• How does humidity affect transpiration rate?

  Decreased humidity increases diffusion rate
• How does air movement affect transpiration rate?

  Increased air movement raises diffusion rate
• How does light intensity affect transpiration rate?

  Increased light opens more stomata
• What is the method for counting stomata on a leaf?

  Take a representative sample
• What must a representative sample include?

  Sufficient random counts across the leaf
• What adaptations do cacti have for desert survival?

  Store water, deep roots, reduced stomata
• What is the purpose of spines on cacti?

  Minimize water loss and protect from animals