Bacteria, Viruses, and Protists

Bacteria Basics

What are the main components of a bacterial cell?

The major components of a bacterial cell are the plasma membrane, cell wall, and a nuclear region containing a single, circular DNA molecule. Plasmids—small circular pieces of DNA that exist independently of the bacterial chromosome—are also present in a bacterial cell. In addition, some bacteria may have flagella (for movement; for more about flagella, see the chapter “Cellular Basics”); pili or fimbriae (short, hairlike appendages that allow certain bacteria to adhere to various surfaces, including the cells that they infect); or a capsule of slime around the cell wall that protects it from other microorganisms.


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