encellede

Encellede is a Danish term that refers to unicellular organisms, i.e., organisms whose bodies consist of a single cell. The category includes both prokaryotes—bacteria and archaea—and many eukaryotic groups, such as various protists, yeasts, and some algae. In this context, unicellular organisms are contrasted with multicellular organisms whose bodies are composed of many cells.

A defining feature of encellede is that every essential function for life occurs within one cell. That single cell carries metabolism, growth, response to the environment, and often movement. Cells vary widely in size, shape, and organization: some are simple and lack internal compartments, while many eukaryotic unicells contain organelles and complex structures. Motility is common in many encellede, achieved through flagella, pseudopods, or cilia; others are non-motile.

Reproduction is typically rapid and often asexual. Bacteria and archaea mainly divide by binary fission, while many unicellular fungi and protists reproduce by budding or simple mitotic division. Some groups also have sexual or genetic exchange stages. Environmental conditions strongly influence growth and forms of metabolism, including photosynthesis in some algae and heterotrophy in many protozoa and yeasts.

Ecology and significance: encellede inhabit virtually every environment, from oceans and soils to extreme habitats. They drive essential ecological processes such as nutrient cycling and primary production. In science and industry, unicellular organisms serve as model systems for cell biology and genetics, and yeasts and other encellede underpin fermentation and biotechnological applications. They are distinct from viruses, which are not cells, and from multicellular organisms, though some multicellular species have unicellular life stages.