What are bacteria classified as in terms of cellular structure?

In terms of cellular structure, bacteria are classified as prokaryotes. This classification is based on several key characteristics that define prokaryotic cells. Prokaryotes are unicellular organisms that lack a defined nucleus and membrane-bound organelles. Instead, their genetic material, usually a single circular DNA molecule, is located in a region of the cell called the nucleoid.

Additionally, prokaryotic cells are typically smaller and simpler in structure compared to eukaryotic cells, which have more complex organization, including compartmentalization with organelles such as mitochondria and the endoplasmic reticulum, as well as a true nucleus.

Bacteria do not possess the multicellular organization found in higher eukaryotic organisms, nor are they virus-like particles, which are acellular entities that require a host to replicate. Understanding these foundational distinctions is essential for characterizing bacteria accurately in microbiology and various laboratory practices.