Translocation

• What do xylem vessels carry in plants?

  Water and dissolved minerals

  
• What do phloem vessels transport around the plant?

  Sugars made in photosynthesis

  
• What is the process called by which phloem vessels transport sugars?

  Translocation

  
• In which direction can sugars be moved by phloem vessels?

  Either up or down the plant

  
• What are the two types of phloem cells and their functions?

  • Sieve tubes:
  • Contain little cytoplasm and no nucleus
  • Have pores in end walls for easy flow
  • Companion cells:
  • Sit alongside sieve tubes
  • Have many mitochondria for energy in active transport

  
• What is the role of companion cells in phloem vessels?

  They provide energy for moving sugars through sieve tubes

  
• What is the main energy source for the movement of water in xylem vessels?

  Thermal energy from the Sun
• What is the main energy source for the movement of sugars in phloem vessels?

  Energy released in respiration

  
• Compare the features of xylem and phloem cells.

  Xylem cells:

  • Dead, empty cells
  • No nucleus, organelles, or cytoplasm
  • No end walls
  • Lignin to waterproof and strengthen walls

  
  

  Phloem cells:

  • Sieve tube cells: No nucleus, few organelles, little cytoplasm, pores in end walls
  • Companion cells: Lots of mitochondria for respiration

  
• What type of energy is used in transpiration for water movement?

  Thermal energy from the sun
• What type of energy is used in translocation for sugar movement?

  Respiration
• What type of tissue is involved in the transport of water?

  Xylem

  
• What type of tissue is involved in the transport of sugars?

  Phloem

  
• What is the direction of water transport in xylem vessels?

  Up the plant

  
• What is the direction of sugar transport in phloem vessels?

  Either up or down the plant

  
• What structural feature of sieve tubes allows substances to flow easily?

  Pores in the end walls
• Why do companion cells have many mitochondria?

  To release energy for moving sugars
• How do the features of xylem cells support their function in water transport?

  They are dead and empty, allowing for efficient water flow
• How do the features of phloem cells support their function in sugar transport?

  Sieve tubes have pores for flow, and companion cells provide energy