Transport tissues - Xylem and phloem

• What is the primary function of xylem tissue?

  Transport water and ions from roots
• What types of cells are found in xylem?

  Xylem vessels, tracheids, and parenchyma
• What do xylem vessels transport?

  Water and minerals
• How do xylem vessels form long tubes?

  Their end walls break down
• What is the function of tracheids in xylem?

  Provide strength to the tissue
• What is the role of xylem parenchyma?

  Act as packing tissue between vessels
• What type of cells are tracheids and xylem vessels?

  Dead cells
• What is the composition of xylem cell walls?

  Made of lignin, impermeable to water
• How does water enter and leave xylem vessels?

  Through holes called pits
• What are protoxylem and metaxylem?

  Young and older xylem, respectively
• What is the primary function of phloem tissue?

  Transport organic molecules
• What type of cells are found in phloem?

  All cells are alive
• What do phloem sieve tubes contain?

  Little cytoplasm and few organelles
• What is the role of companion cells in phloem?

  Support sieve tube cells and transport substances
• What do companion cells contain that is crucial for their function?

  Numerous mitochondria
• How do companion cells and sieve tube elements connect?

  Via plasmodesmata
• What are sieve plates in phloem?

  Perforated end walls of sieve tubes
• What passes through the pores of sieve plates?

  Strands of cytoplasm
• What are the components of vascular bundles?

  • Xylem
  • Phloem
  • Cambium
  • Other cells
• What is cambium in vascular bundles?

  A meristematic tissue that divides by mitosis
• What happens to cambium cells after division?

  They differentiate into other cells
• Where do vascular tissues form in a dicot stem?

  Around the periphery of the stem