Here's why:

* E. coli is a bacteria. Bacteria are classified as prokaryotes.

* Prokaryotes are single-celled organisms that lack a nucleus and other membrane-bound organelles.

* E. coli's cell structure includes:

* Cell membrane: Encloses the cell and regulates what enters and exits.

* Cell wall: Provides structural support and protection.

* Cytoplasm: The gel-like substance inside the cell where metabolic processes occur.

* Ribosomes: Sites of protein synthesis.

* DNA: Located in a region called the nucleoid, but not enclosed by a membrane.

Let me know if you have any other questions about E. coli or prokaryotic cells!