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Which of the following is NOT a characteristic feature of collenchyma cells?
Presence of lignin in cell walls
Unevenly thickened cell walls
Living cells at maturity
Provides flexible support to the plant
The flexibility of collenchyma tissue is primarily attributed to:
The presence of lignin in the cell wall
The thin cell walls
The combination of pectin and hemicellulose in the cell wall
The intercellular spaces present between the cells
Which statement BEST describes the relationship between collenchyma and sclerenchyma?
Both are composed of living cells at maturity.
Both have evenly thickened cell walls.
Both contain lignin in their cell walls.
Both provide structural support, but collenchyma provides flexible support in growing regions while sclerenchyma provides rigid support in mature regions.
How does the arrangement of cellulose microfibrils in the secondary cell walls of xylem vessels contribute to their function?
Facilitates rapid water flow through the vessel lumen
Increases the flexibility of the vessel walls
Provides strength and prevents collapse under negative pressure
Regulates the passage of ions and nutrients into the xylem sap
Which specific characteristic of sclerenchyma cells primarily contributes to their exceptional strength and rigidity, making them suitable for providing structural support in plants?
Presence of lignin in the secondary cell wall
High concentration of pectin in the middle lamella
Presence of living protoplasts at maturity
Thin and flexible primary cell wall
Considering the structural adaptations of sclerenchyma, which of these statements best explains why these cells are typically dead at maturity?
The heavily lignified cell wall restricts the entry of essential substances for cellular metabolism.
Sclerenchyma cells actively undergo programmed cell death during development to enhance structural integrity.
The lack of a nucleus and other organelles reduces the metabolic burden, optimizing the cell for support.
Sclerenchyma cells are produced in excess and are shed as the plant grows, similar to epidermal cells.
Which statement correctly describes the relationship between the pit canals and the function of sclerenchyma fibers?
Pit canals allow for limited intercellular communication and nutrient transport, even though the cells are typically dead at maturity.
Pit canals are sites of active lignin synthesis, contributing to the thickening of the secondary cell wall.
Pit canals weaken the cell wall, providing flexibility to the sclerenchyma fibers.
Pit canals store water, allowing sclerenchyma cells to survive in arid conditions.
Which of the following is a characteristic feature of collenchyma cells?
Thickened cell walls at the corners
Uniformly thickened cell walls
Presence of lignin in cell walls
Dead at maturity
Which component is primarily responsible for the thickening of collenchyma cell walls?
Pectin
Lignin
Suberin
Cutin
What type of thickening is observed in the cell walls of collenchyma tissue?
Uneven thickening
Uniform thickening
No thickening
Spiral thickening
