Transport in plants

• What is the main function of the vascular system in plants?

  Transport water and nutrients
• Why do multicellular plants need transport systems?

  To efficiently move substances throughout the plant
• What is the purpose of staining plant tissue?

  To visualize xylem and phloem distribution
• How are xylem and phloem arranged in dicotyledonous plants?

  Xylem inside, phloem outside in bundles
• What is the shape of the xylem in young roots?

  Often in the shape of an X or star
• What role does the endodermis play in plant roots?

  It helps transport water and minerals
• How does the arrangement of vascular bundles change in woody plants as they grow?

  They become a continuous ring near the outer edge
• What is the function of the vascular bundles in leaves?

  To form the midrib and branching network
• What is required to examine vascular tissue in plants?

  Staining of the tissue
• What are companion cells in phloem tissue?

  Cells that help load sucrose into sieve tubes
• What do sieve plates in phloem contain?

  Tiny holes for sap flow
• What is the primary function of xylem tissue?

  Transport water and mineral ions
• How does lignin affect xylem vessels?

  Makes walls waterproof and prevents collapse
• Why are xylem vessels aligned end to end?

  To form a continuous column for water transport
• What is the main function of phloem tissue?

  Transport assimilates like sucrose
• Why do sieve tube elements lack a nucleus?

  To allow space for mass flow of sap
• What is a sink in the context of phloem transport?

  Any area that removes sucrose from phloem
• How does water enter the phloem?

  Through the sieve plates under high pressure
• What are the three pathways taken by water through a plant?

  Apoplast, symplast, and vacuolar pathways
• What characterizes the apoplast pathway?

  Water moves through cell walls without membranes
• How does the symplast pathway differ from the apoplast pathway?

  Water passes through plasma membranes into cytoplasm
• What is the vacuolar pathway in plants?

  Water moves through vacuoles as well as cytoplasm
• Why is mass flow important in plant transport systems?

  It allows efficient movement of substances
• Why do plants not need a transport system for gases like oxygen?

  Gases diffuse directly through cell membranes
• What is the difference between diffusion and mass flow?

  Diffusion is passive, mass flow is active
• Why is mass flow considered the best way to transport substances in plants?

  It ensures rapid and efficient distribution
• What is the role of plasmodesmata in plant cells?

  Connects cytoplasm of adjacent cells
• How does the structure of xylem support its function?

  Dead cells form a continuous water column
• How do companion cells support phloem function?

  They provide ATP for loading assimilates
• Why do phloem sieve tube elements lack lignin?

  To allow flexibility and facilitate transport
• What is the primary role of xylem vessels?

  Transport water and minerals
• What is the significance of bordered pits in xylem vessels?

  Allows lateral water movement between vessels
• How does the structure of phloem differ from that of xylem?

  Phloem has living cells, xylem has dead cells
• What is the function of sieve plates in phloem?

  Facilitate the flow of phloem sap
• What is the main component of phloem sap?

  Sucrose and amino acids
• How does water potential change at the sink in phloem transport?

  It becomes less negative as water moves out
• What happens to the hydrostatic pressure in the phloem at the sink?

  It decreases as sucrose is removed
• Why is the movement of water through plants essential?

  It supports photosynthesis and nutrient transport
• What is the role of the vacuolar pathway in water movement?

  Allows water to pass through vacuoles
• How does the apoplast pathway differ from the symplast pathway?

  Apoplast does not enter cells, symplast does