Bacterial

Bacterial is an adjective relating to bacteria, the large domain of prokaryotic microorganisms. Bacteria are a diverse group found in nearly every habitat on Earth. They range in size and shape, from cocci and bacilli to spirilla and vibrios, and they may exist as single cells or in colonies. Most have a cell envelope consisting of a cytoplasmic membrane and a peptidoglycan cell wall; some lack cell walls or have additional layers such as capsules.

Genetic material is a single circular chromosome located in the nucleoid, and many species carry plasmids that can be exchanged through horizontal gene transfer.

Metabolism is diverse. Bacteria can be autotrophic, using light or chemical energy, or heterotrophic, obtaining carbon from organic molecules. Photosynthesis is performed by cyanobacteria; some bacteria fix nitrogen; respiration can be aerobic or anaerobic.

Reproduction is mainly by binary fission, which allows rapid population growth. Genetic exchange can occur via transformation, transduction, and conjugation, contributing to adaptation and antibiotic resistance.

Ecology and health: They are essential decomposers, participate in nutrient cycling, and form symbiotic relationships with hosts. Some bacteria cause diseases, while many are harmless or beneficial. Bacterial communities in the human microbiome influence digestion, immunity, and metabolism.

Applications and detection: Bacteria are used in biotechnology for producing enzymes, pharmaceuticals, and fermented foods; model organisms like Escherichia coli aid research. Detection methods include culturing, microscopy with Gram staining, and molecular techniques such as sequencing.

Taxonomy: Bacteria are one of the three domains of life, distinct from Archaea and Eukaryota. They are further divided into many phyla based on genetic and phenotypic traits; Gram staining distinguishes Gram-positive from Gram-negative cell envelopes.