Organenes

Organenes, more commonly called organelles in modern biology, are specialized structures within cells that perform dedicated tasks essential for cellular life. In eukaryotic cells, organenes are typically enclosed by their own membranes, creating distinct compartments that isolate chemical reactions. In prokaryotic cells, such membrane-bound organenes are rare, though some bacteria have specialized compartments.

Examples include nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, ribosomes, vacuoles, and vesicles. The nucleus houses genetic material and coordinates gene expression. Mitochondria generate ATP via respiration and contain their own DNA and ribosomes. Chloroplasts carry out photosynthesis in plants and algae and also contain DNA. Endoplasmic reticulum comes in rough and smooth forms; rough has ribosomes for protein synthesis; smooth synthesizes lipids and detoxifies. The Golgi apparatus modifies, sorts, and ships proteins and lipids. Lysosomes digest macromolecules; peroxisomes metabolize fats and detoxify. Ribosomes synthesize proteins, not surrounded by a membrane; they can be free or attached to ER. Vacuoles serve storage and maintenance, especially large central vacuoles in plant cells.

Structure and origin: Many organelles are bounded by double membranes; mitochondria and chloroplasts have circular DNA and ribosomes similar to bacteria, supporting endosymbiotic theory. Others are formed by budding or vesicular trafficking. Size varies from 10 nm to several micrometers.

Function and significance: Compartmentalization allows specialization, regulation, and efficient metabolism, and organelle dysfunction underlies many diseases. Modern research uses light and electron microscopy, cell fractionation, and omics to study organelle composition and function.

Etymology: The term organenes is uncommon in English; organelle is the standard term; some sources may use organenes in other languages or older literature.