The Casparian strip is impregnated with which substance?
Answer: B
The Casparian strip in endodermis is impregnated with suberin, making it impermeable to water and solutes, thus forcing them through the endodermal cells.
Q.22Medium
Which of the following represents the correct sequence of tissue layers from outside to inside in a dicot stem?
Answer: C
In a young dicot stem, the sequence from outside is: cuticle, epidermis, cortex (containing hypodermis and endodermis), vascular bundles, and central pith.
Q.23Medium
In monocot roots, the pericycle is typically:
Answer: A
In monocot roots, the pericycle is usually uniseriate and gives rise to lateral roots, unlike in dicots where it's multiseriate.
Q.24Medium
Which adaptation in desert plants helps reduce water loss through leaves?
Answer: B
Desert plants (xerophytes) have smaller leaves, thicker cuticles, and often sunken stomata to minimize water loss through transpiration.
Q.25Medium
In aquatic plants, the aerenchyma tissue functions primarily to:
Answer: B
Aerenchyma is specialized parenchyma with large air spaces that provides buoyancy and allows diffusion of gases in hydrophytes.
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Q.26Medium
The cork cambium (phellogen) originates from:
Answer: C
The cork cambium originates from the endodermis or outer cortical cells and produces cork and phelloderm as part of the periderm.
Q.27Medium
The xylem in angiosperms is primarily composed of:
Answer: C
Angiosperm xylem consists of vessels (main conducting element), tracheids, xylem parenchyma (storage), and xylem fibers (support).
Q.28Medium
Which anatomical adaptation is specific to insectivorous plants like pitcher plants?
Answer: B
Insectivorous plants have anatomically modified leaves (pitchers, traps) with specialized glandular and digestive tissues to trap and digest insects.
Q.29Medium
The Casparian strip found in the endodermis of roots is composed primarily of:
Answer: A
The Casparian strip is an impermeable band of suberin and lignin that prevents lateral movement of water and minerals, forcing them through the endoderm symplastically.
Q.30Medium
Which anatomical feature distinguishes the anatomy of a typical dicot leaf petiole from that of a monocot?
Answer: A
Dicot petioles typically have multiple vascular bundles arranged in a ring or scattered pattern, while monocots have scattered bundles throughout.
Q.31Medium
Tracheids differ from vessel elements in that tracheids:
Answer: A
Tracheids lack perforation plates, have oblique overlapping end walls with bordered pits, and are found in both gymnosperms and angiosperms, conducting water more slowly than vessel elements.
Q.32Medium
The mestome sheath observed in some monocot leaves functions primarily to:
Answer: A
The mestome sheath, composed of sclerenchyma fibers, surrounds the vascular bundle and provides mechanical strength to the leaf structure.
Q.33Medium
The phenomenon of radial vascular bundles is characteristic of:
Answer: A
Radial arrangement of xylem and phloem in alternate pattern is typical of dicot roots, where xylem arms point toward the periphery and phloem patches lie between them.
Q.34Medium
Companion cells in angiosperms are specifically associated with:
Answer: A
Companion cells are living cells derived from the same mother cell as sieve tubes; they provide metabolic support and regulate loading/unloading of photosynthates.
Q.35Medium
In hydrophytic plants, aerenchyma tissue is primarily composed of:
Answer: A
Aerenchyma consists of large air-filled intercellular spaces that facilitate gas exchange and provide buoyancy in aquatic plants.
Q.36Medium
The anatomical basis for the superior mechanical strength of dicot stems compared to monocot stems is:
Answer: A
Dicots develop secondary tissues (secondary xylem and phloem) through vascular cambium activity, creating dense wood that provides greater mechanical strength than herbaceous monocots.
Q.37Medium
In gymnosperms, the conducting tissue in xylem is primarily composed of:
Answer: A
Gymnosperms lack vessel elements and rely on tracheids with bordered pits for water conduction, which is less efficient than angiosperm vessel elements.
Q.38Medium
The anatomical adaptation of sunken stomata in xerophytes is primarily effective because it:
Answer: A
Stomatal pits create a humid chamber that reduces the vapor pressure gradient between intercellular spaces and external environment, thereby minimizing transpirational water loss.
Q.39Medium
The presence of sclerenchyma fibers in the phloem tissue (phloem fibers) primarily serves to:
Answer: A
Phloem fibers (bast fibers) provide mechanical support to vascular bundles and stems while permitting the translocation function of sieve tubes and companion cells.
Q.40Medium
Companion cells in phloem are primarily associated with:
Answer: B
Companion cells are closely associated with sieve tube elements and help in loading and unloading of sucrose and control of sieve tube functioning.
