Daily Olympiad: Biology - Structural Organisation [20260511]

Solution

Correct: C

Sclerenchyma cells have walls thickened with lignin, providing mechanical strength and rigidity to plant structures. Parenchyma is simple and thin-walled; collenchyma has uneven thickening; meristematic tissues are undifferentiated.

Solution

Correct: C

The basal layer of stratified squamous epithelium is mitotically active, replenishing the outer layers that undergo keratinization. Secretion (glandular epithelium) and absorption (columnar epithelium) are unrelated functions. Desmosis is a junctional structure, not a regenerative process.

Solution

Correct: B

Bone matrix contains calcium salts (hydroxyapatite crystals) which give rigidity. Cartilage matrix is rich in chondroitin sulfate and lacks calcium crystals. Blood and areolar tissue have fluid or loose matrix.

Solution

Correct: B

Insect tracheae are lined with simple squamous epithelium containing chitin but no cilia. Ciliated structures are for mucous transport, pseudostratified for respiratory tracts in vertebrates, and cuboidal for secretory glands.

Solution

Correct: B

Sunken stomata in stomatal crypts reduce transpiration in xerophytes. Epidermal cells don't store water; vascular bundles in xerophytes are clustered for efficient transport. Palisade mesophyll is present for photosynthesis.

Solution

Correct: A

Goblet cells are unicellular glands embedded in epithelium, secreting mucus to lubricate and protect surfaces like bronchus. Their function is distinct from nutrient absorption or ion transport mechanisms.

Solution

Correct: C

Cardiac muscle cells are uninucleate with central nuclei. Skeletal muscles are multinucleated with peripheral nuclei. All other options are unique to cardiac muscle.

Solution

Correct: B

Sieve tube members have secondary thickening in their radial walls due to spiral or reticulate patterns. Vessel elements and tracheids have annular/lacunar thickenings, while companion cells lack secondary walls.

Solution

Correct: D

Internodes are myelinated segments of axons insulated by Schwann cell membranes. Nodes of Ranvier are gaps between internodes where axon is exposed, allowing saltatory conduction.