User talk:2409:40D2:4E:991A:8000:0:0:0

Classification of bacteria Bacteria are the smallest organism having a cellular structure,their avrage diameter being about 1nm. A single drop of water may contain 5×10⁶ bacteria.Thiophysa volutans,a suphur bacterium, measuring about 18nm in diameter, is perhaps the largest amongst all bacteria. They can be classified on the basis on their shape, nutrition and mode of respiration