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.
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
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
Considering the isobilateral nature of most monocot leaves, how does the distribution of stomata differ from that of a typical dorsiventral dicot leaf?
Stomata are absent in monocot leaves.
Stomata are only present on the upper surface in monocots.
Stomata are relatively evenly distributed on both surfaces in monocots, while they are predominantly on the lower surface in dicots.
Stomata are clustered around the vascular bundles in monocots.
The lignified secondary walls of xylem elements provide:
Flexibility for bending and twisting
Storage of water and nutrients
Mechanical strength and prevention of collapse under tension
Increased surface area for water absorption
The flow of water through xylem is primarily:
Bidirectional
Multidirectional
Unidirectional
Random
The primary function of the stomata in a dicot leaf is:
Photosynthesis
Water storage
Gas exchange and transpiration
Sugar transport
During periods of extreme dryness, the leaves of grasses often curl inwards. What is the primary reason for this adaptation?
To increase sunlight absorption
To protect against herbivores
To trap more carbon dioxide
To minimize water loss through transpiration
Which of the following best explains why grass leaves curl inwards under drought conditions?
Increased sunlight reflection
Enhanced carbon dioxide uptake
Protection from insect damage
Reduction of transpiration rate
How does the inward curling of leaves benefit grasses in arid environments?
Increases light absorption for photosynthesis
Improves nutrient uptake from the soil
Protects against herbivore grazing
Reduces water loss through transpiration
