The structure of L. acidophilus has many characteristics. This bacterium is a single-celled prokaryotic microorganism that lacks a distinct nucleus. Although, there are many other parts to the cell of this bacterium such as having: a cell wall, a cytoplasmic membrane, a nucleoid, cytoplasm, ribosomes, pili, and flagella. The overall shape of L. acidophilus is one that is rod shaped. This bacterium occurs in small chains and is usually 0.5 to 0.8 micrometre (1 mm=10^-6 metre) across by 2 to 9 mm in length. It is also important to note that L. acidophilus is non-spore-forming. 

                                       These are both pictures of the structure of L. acidophilus.