MCQs

Cutin is a complex macromolecular lipid polymer that coats the outer surfaces of land plants, reducing non-stomatal transpirational water loss.

The central vacuole maintains an acidic internal pH and houses a variety of hydrolytic enzymes to break down and recycle macromolecules.

Animal cells rely on an intricate network of specialized junctional complexes to bind cells structurally and coordinate tissue-wide communication.

Intermediate filaments (like keratins, lamins, and vimentin) possess high tensile strength, protecting animal cells from stretching and tearing.

Peroxisomes host amino acid and fatty acid oxidation reactions that generate hazardous H2​O2​, which is immediately neutralized by catalase.

Hydrostatic turgor pressure pushes cells tightly against one another, providing mechanical structural support to non-woody plant organs.

Fungi utilize chitin (a polymer of N-acetylglucosamine) for structural support, while plants rely on cellulose.

The interlaced arrangement of cellulose microfibrils leaves large physical pores that allow water and small solutes to diffuse freely.

The spindle apparatus, built from tubulin heterodimers, attaches to kinetochores to pull chromosomes to opposite poles in all eukaryotic cells.

The secondary wall is thick and contains dense cellulose and lignin, providing structural reinforcement to mature, non-growing plant tissues.

The primary cell wall is laid down by expanding cells; it is thin, extensible, and flexible, accommodating cell growth and elongation.

Elaioplasts are specialized, non-pigmented plastids dedicated to storing lipids and essential fatty oils inside plant seeds or leaves.

Apoptosis is a highly regulated programmed cell death mechanism central to animal development, tissue homeostasis, and defense.

The middle lamella is rich in pectin salts (calcium and magnesium pectates), which cross-link to form a sticky, cementing extracellular layer.

Without an external wall to anchor its shape, an animal cell losing water collapses completely, shriveling into a wrinkled, crenated morphology.

Plant cells lack discrete centrioles but possess diffuse, membrane-associated MTOCs that organize the cytoskeletal tracking networks.

The thylakoid membranes inside chloroplasts house the photosystems, electron transport chains, and ATP synthase machinery needed for light harvesting.

The rigid plant cell wall serves as a physical barrier that prevents the invagination of the plasma membrane required for endocytosis.

Chromoplasts contain lipid-soluble carotenoids and develop from chloroplasts or leukoplasts, serving to attract pollinators and seed dispersers.