JNTU B.Pharmacy I Year REMEDIAL BIOLOGY Previous Question Paper (October-2020 - R17)

The anatomy of dicotyledonous plants is characterized by specific tissue arrangements that support growth and transport. The primary structures are as follows:

1. Dicot Root: The transverse section reveals an outer layer called the epiblema (or epidermis) with unicellular root hairs. Beneath this lies the cortex, consisting of several layers of thin-walled parenchyma cells. The innermost layer of the cortex is the endodermis, which contains Casparian strips. The stele includes the pericycle and vascular bundles, which are radial and typically tetrarch (four xylem and four phloem patches). A central pith is usually absent or very small.

2. Dicot Stem: The epidermis is covered by a cuticle and may contain trichomes. The cortex is differentiated into three regions: the outer hypodermis (collenchyma), middle parenchyma, and inner endodermis (starch sheath). The vascular bundles are arranged in a ring; each bundle is conjoint, collateral, and open (possessing cambium for secondary growth). The center of the stem is occupied by a well-developed pith composed of parenchyma cells.

3. Dicot Leaf (Dorsiventral): The leaf is differentiated into two surfaces: the adaxial (upper) and abaxial (lower) epidermis, both covered by a cuticle. The mesophyll tissue, located between the epidermal layers, is specialized into two types: the palisade parenchyma (vertically elongated cells on the upper side) and the spongy parenchyma (loosely arranged cells with air cavities on the lower side). The vascular bundles are found in the veins and are surrounded by a layer of thick-walled bundle sheath cells.

Kingdom Plantae comprises multicellular, eukaryotic, autotrophic organisms that possess cell walls made of cellulose. Their primary characteristics include:

• Photosynthesis: They contain chlorophyll pigments within chloroplasts, allowing them to synthesize organic food from inorganic raw materials using sunlight.
• Cell Wall: A rigid outer layer composed mainly of cellulose provides structural support and protection.
• Alternation of Generations: They exhibit a life cycle that alternates between a diploid sporophyte generation and a haploid gametophyte generation.
• Growth: Growth is generally localized in meristematic regions and is indeterminate, meaning they continue to grow throughout their lifespan.
• Immobility: They are typically sessile, lacking the ability to move from one place to another.

Kingdom Animalia consists of multicellular, eukaryotic, heterotrophic organisms that lack cell walls. Their primary characteristics include:

• Heterotrophic Nutrition: Animals cannot produce their own food and must ingest organic matter, which is then digested internally.
• Cell Structure: Animal cells lack a cell wall and chloroplasts, possessing only a flexible plasma membrane, which allows for greater mobility.
• Locomotion: Most animals possess specialized contractile tissues (muscles) and nervous systems that enable active, coordinated movement in response to environmental stimuli.
• Sensory and Nervous Systems: They possess highly developed sensory organs and nervous systems to process information and coordinate complex behaviors.
• Determinate Growth: Growth typically follows a set pattern and stops once the organism reaches maturity.
• Reproduction: Most animals reproduce sexually, involving the fusion of haploid gametes to form a diploid zygote, which undergoes complex embryonic development.