baktérion

Baktérion is a term used in biology to refer to bacteria, typically single-celled prokaryotic microorganisms. The name derives from Greek baktērion meaning “a little staff” or “rod,” a reference to the common shape of many species. In everyday usage, baktérion can denote either bacteria as a group or a single bacterial cell.

Cell structure: Baktérions are prokaryotes, lacking a membrane-bound nucleus. Their genetic material is usually a single circular chromosome located in the nucleoid, and many carry small DNA molecules called plasmids. Most have a cell wall; the chemical composition often distinguishes two major groups: Gram-positive and Gram-negative. Cellular shapes include cocci (spherical), bacilli (rod-shaped), and spirilli. Some have flagella or pili to move or attach to surfaces.

Metabolism and growth: Baktérions display diverse metabolisms. They can be autotrophic, using light (phototrophs) or inorganic compounds (chemotrophs) for energy, or heterotrophic, consuming organic compounds. They can be aerobic, anaerobic, or facultatively anaerobic. Reproduction is typically asexual, most commonly by binary fission.

Ecology and significance: They are ubiquitous, inhabiting soil, water, air, and living hosts. They play essential roles in nutrient cycles, such as carbon and nitrogen cycles, and in fermentation and biotechnology. Some baktérions form symbiotic relationships with plants or animals; others are pathogens capable of causing disease.

Study and applications: Baktérions are studied in microbiology, molecular biology, and ecology. They are detected by staining, culturing, microscopy, and sequencing. Culturing is possible for many species but not for all. Advances in genomics and metagenomics have expanded access to unculturable baktérions, revealing vast diversity and ecological functions.

Health and risk: The relationship with humans ranges from beneficial microbiota to infectious agents. Antibiotic resistance and emerging pathogens are ongoing public health concerns, guiding surveillance and research.