A bacterium is a single-celled microorganism belonging to the domain Bacteria, which are characterized by their relatively simple cellular structure and lack of a nucleus. These microorganisms are incredibly diverse, inhabiting various environments ranging from soil and water to the human body and are known for their ability to adapt and survive in extreme conditions.
Bacteria are prokaryotes, meaning their genetic material, contained in a circular chromosome, is not enclosed within a membrane-bound nucleus. They reproduce asexually through binary fission, where a single cell divides into two identical daughter cells.
Bacteria play a crucial role in various biological processes, including nutrient cycling, and they can have both positive and negative impacts. Some bacteria form symbiotic relationships with their hosts, providing benefits such as aiding digestion or producing vitamins, while others cause infections and diseases such as pneumonia or cholera.
The size of bacteria can vary greatly, with some measuring only a few micrometers in length, while others can be visible to the naked eye, as with the colonies of bacteria forming films or mats. They can have various shapes, including spherical (cocci), rod-like (bacilli), or spiral (spirilla), and their outer cell walls are composed of unique substances, such as peptidoglycan.
The study of bacteria, known as bacteriology, has greatly contributed to our understanding of microscopic life, and their importance in ecosystems, industry, and medicine cannot be overstated.
