Bacteria do not have any cell walls, however, all bacteria have a protective cell membrane that encases their cytoplasm. Genetic data and other biological structures essential for cell function are found in cytoplasm.
Bacteria have a semi-permeable cell membrane which deters unwanted foreign materials from entering the cell while permitting nutrients and substances to pass through. Bacteria are single-celled organisms that do not contain a nucleus or the organelles that are found in more complex organisms. Their DNA is contained in a small loop found in the cytoplasm, and may also be found in other genetic structures known as plasmids.