Prepare for NEET Biology Anatomy of Flowering Plants with MCQs & PYQs on NEET.GUIDE. Enjoy free practice, previous year questions, and expert insights on plant tissues and structures.
In a dicot root undergoing secondary growth, the phellogen typically originates from which tissue layer?
Cortex
Endodermis
Pericycle
Phloem
Which feature distinguishes the conjunctive tissue in a dicot root from the typical parenchyma found in the cortex?
Presence of intercellular spaces
Thin-walled cells with large vacuoles
Sclerenchymatous nature in mature roots providing mechanical support
Abundant chloroplasts for photosynthesis
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.
Sclereids are a type of sclerenchyma cell. Which of these is NOT a typical characteristic of sclereids?
Forming continuous, elongated fibers in plant stems
Occurring singly or in small groups within other tissues
Having highly thickened and lignified cell walls
Varying greatly in shape, from isodiametric to branched
The gritty texture of pear fruit is due to the presence of:
Stone cells (sclereids)
Collenchyma cells
Parenchyma cells
Xylem vessels
In a plant adapted to arid conditions, you would expect to find a higher proportion of sclerenchyma tissue in which region, and for what primary purpose?
Stem, to provide structural support against strong winds and reduce water loss
Leaves, to increase photosynthetic efficiency in harsh sunlight
Roots, to enhance water absorption from deep soil layers
Flowers, to attract pollinators in a resource-scarce environment
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.
In a monocot root, the passage cells of the endodermis are characterized by all of the following EXCEPT:
Retention of thin walls with minimal suberin deposition
Location opposite to the protoxylem points
Facilitation of water and mineral transport to the xylem
Thickened Casparian strips on all walls
The multilayered pericycle in a monocot root contributes significantly to:
Lateral root formation
Secondary growth
Vascular cambium formation
Primary xylem development
