Structure and Function

Listeria is a rod shaped bacteria but it can also be found in the form chains of rod shaped bacteria. They are prokaryotic eubacteria (single celled) and contain a plasma membrane, cell wall, ribosomes, and nucleic acid. The bacteria is found to be 0.8-2.6 nanometers in length and 0.6-0.9 nanometers in diameter. They do not reproduce through spores and are non photosynthetic, instead it reproduces through binary fission.

An example of listeria in it's rod shape
From http://www.kimicontrol.com/microorg/Listeria%20monocytogenes.jpg

Listeria is also known to be gram positive, which means that when stained during a gram test the result is a violet or blue – instead of pink or red (gram negative). This shows that the bacteria is likely to not have a thick outer cell wall membrane but has a thick layer of peptidoglycan (a layer around the plasma membrane made of amino acids and sugars) in the cell wall.

Listeria stained during a gram test. Showing violet color therefore gram positive.
From http://coproweb.free.fr/pagbac/introbac/listeria.htm

They move about using flagellum at room temperature (24 degrees) or actin tails provided from host cells at body temperature (37 degrees).