,QUESTION 1
List the cell types concerned with transport of water
in angiosperms, and briefly
explain the differences between these cell types. (10)
QUESTION 1: Cell Types Concerned with
Transport of Water in Angiosperms
In angiosperms, water transport primarily occurs
through two types of cells: xylem
vessels and tracheids. Both are specialized for water
conduction but differ in structure and function.
1. Xylem Vessels:
o Structure: Xylem vessels are long, tube-like
structures formed by the end-to-end fusion
of vessel elements. They have perforated
end walls (perforation plates) that allow
continuous water flow.
o Function: They are highly efficient in water
transport due to their wide lumen and lack
of end walls, enabling rapid movement of
water and dissolved minerals.
o Distribution: Found mainly in angiosperms.
, 2. Tracheids:
o Structure: Tracheids are elongated, spindle-
shaped cells with tapered ends. They have
pits (thin areas in the cell wall) for water
movement between adjacent cells.
o Function: They transport water and provide
mechanical support to the plant. Water
moves through pits, which slows the flow
compared to vessels.
o Distribution: Found in both angiosperms
and gymnosperms.
Key Differences:
Efficiency: Vessels are more efficient due to
their continuous lumen, while tracheids are less
efficient due to pit-mediated water flow.
Support: Tracheids provide better mechanical
support due to their thick cell walls.
Presence: Vessels are mostly found in
angiosperms, while tracheids are present in both
angiosperms and gymnosperms.
List the cell types concerned with transport of water
in angiosperms, and briefly
explain the differences between these cell types. (10)
QUESTION 1: Cell Types Concerned with
Transport of Water in Angiosperms
In angiosperms, water transport primarily occurs
through two types of cells: xylem
vessels and tracheids. Both are specialized for water
conduction but differ in structure and function.
1. Xylem Vessels:
o Structure: Xylem vessels are long, tube-like
structures formed by the end-to-end fusion
of vessel elements. They have perforated
end walls (perforation plates) that allow
continuous water flow.
o Function: They are highly efficient in water
transport due to their wide lumen and lack
of end walls, enabling rapid movement of
water and dissolved minerals.
o Distribution: Found mainly in angiosperms.
, 2. Tracheids:
o Structure: Tracheids are elongated, spindle-
shaped cells with tapered ends. They have
pits (thin areas in the cell wall) for water
movement between adjacent cells.
o Function: They transport water and provide
mechanical support to the plant. Water
moves through pits, which slows the flow
compared to vessels.
o Distribution: Found in both angiosperms
and gymnosperms.
Key Differences:
Efficiency: Vessels are more efficient due to
their continuous lumen, while tracheids are less
efficient due to pit-mediated water flow.
Support: Tracheids provide better mechanical
support due to their thick cell walls.
Presence: Vessels are mostly found in
angiosperms, while tracheids are present in both
angiosperms and gymnosperms.
