Prepare for NEET with Botany-specific practice questions. Covering all major Botany chapters, this is perfect for your NEET Biology needs.
A researcher is studying the transport of water in a genetically modified plant where the lignin biosynthesis pathway is disrupted. Which of the following is the MOST likely consequence observed in the xylem of this plant?
Increased tensile strength of xylem vessels and enhanced water transport
Collapsed xylem vessels and reduced water transport efficiency
No significant change in xylem structure or water transport
Increased flexibility of xylem vessels and improved water transport under stress
Which of the following BEST explains why the ascent of sap in tall trees is primarily attributed to the cohesion-tension theory rather than root pressure?
Root pressure only operates during the night
Root pressure is primarily involved in nutrient transport, not water transport
Root pressure alone cannot generate sufficient pressure to overcome the gravitational force in tall trees
The cohesion-tension theory is more energy-efficient than root pressure
The specific arrangement of sieve elements and companion cells in phloem tissue, where a single companion cell is associated with multiple sieve elements, is MOST characteristic of which plant group?
Angiosperms
Gymnosperms
Bryophytes
Pteridophytes
Which specific plasmodesmatal characteristic is crucial for the symplastic loading of sucrose into the phloem's sieve element-companion cell complex?
Absence of plasmodesmata between companion cells and sieve elements
Uniformly distributed plasmodesmata with a low density throughout the phloem
Branched plasmodesmata with a high density between companion cells and bundle sheath cells
Numerous plasmodesmata between companion cells and surrounding parenchyma cells, but few between companion cells and sieve elements
During secondary growth in dicot roots, which tissue initiates the formation of the vascular cambium?
The innermost layer of the cortex
The pericycle cells opposite to the protoxylem poles
The pith parenchyma cells
Partly from the pericycle and partly from the conjunctive parenchyma cells lying just below the phloem bundles
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.
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 dicot stem undergoing secondary growth, the cells of the vascular cambium divide to produce secondary xylem and phloem. If a tangential section is taken through the secondary xylem, what would be the predominant cell type observed in terms of arrangement?
Radially arranged parenchyma cells
Axially elongated tracheary elements
Isometric sclerenchyma cells
Clustered secretory cells
Which of the following characteristics distinguishes the periderm from the epidermis in a woody dicot stem?
Presence of stomata
Single-layered structure
Presence of suberized cells
Origin from the ground meristem
