What type of organisms are classified as bacteria?

Bacteria are classified as unicellular prokaryotes, which means they are single-celled organisms that lack a defined nucleus and membrane-bound organelles. This classification is fundamental in understanding the structure and function of bacteria. Prokaryotes are characterized by their simple cell structure, which typically includes a cell wall, plasma membrane, cytoplasm, and genetic material organized in a single circular chromosome.

In contrast to eukaryotic cells, which have complex structures and can be multicellular (like plants and animals) or unicellular (like yeast), prokaryotic cells represent a distinct domain of life. This fundamental difference in cellular organization is crucial for understanding biological processes like reproduction, metabolism, and adaptation in different environments.