CELL STRUCTURE & FUNCTION

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

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

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

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

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

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

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

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

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

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

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

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

Glyoxysomes are temporary, specialized plant peroxisomes that play an essential role in transforming stored seed lipids into transportable sugars.

Plant Golgi bodies exist as multiple disconnected stacks called dictyosomes distributed throughout the cytoplasm, rather than a single large complex.

The cross-linked network of cellulose microfibrils embedded in a matrix of pectin and hemicellulose provides massive tensile resistance against lysis.

Proteins and lipids are glycosylated in the rough ER lumen and sorted in the Golgi complex before being exported to form the animal glycocalyx.

Pectins are branched, hydrophilic polysaccharides that bind water and calcium ions, creating a flexible, hydrated gel matrix in primary walls.

Microfilaments made of actin interact with myosin motor proteins to generate the mechanical constricting force required for the cleavage furrow.

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