prókaryótum

Prokaryotes are single-celled organisms that lack a membrane-bound nucleus and other membrane-bound organelles. Their genetic material, typically a single circular chromosome, is located in a region called the nucleoid. Prokaryotes are divided into two major domains: Bacteria and Archaea. While both are microscopic and share basic cellular structures, they differ significantly in their biochemistry, genetics, and evolutionary history.

Bacterial cells are characterized by a cell wall, usually composed of peptidoglycan, which provides structural support and protection. They also possess a cell membrane, cytoplasm, ribosomes for protein synthesis, and often flagella for motility. Bacteria are incredibly diverse, inhabiting almost every environment on Earth, from soil and water to the bodies of other organisms. They play crucial roles in ecosystems, including nutrient cycling and decomposition, and some are also known for causing diseases.

Archaea, on the other hand, have cell walls that lack peptidoglycan and often have unique lipid compositions in their cell membranes. Many archaea are extremophiles, thriving in harsh conditions such as high temperatures, high salt concentrations, or anaerobic environments. While some archaea are found in common environments like soil and oceans, they are particularly abundant in extreme habitats. Despite their distinct characteristics, Archaea share some fundamental molecular processes with eukaryotes, suggesting a closer evolutionary relationship than previously thought. The study of prokaryotes is vital for understanding the origins of life, microbial ecology, and developing biotechnological applications.