Structure of E. coli bacteria.
Shape: minute and rod-like
Size: Length, 2 – 4 m; width, 0.5-1 m
1) They are gram-negative, ie they lose their colour when they are washed with sprit after their being coloured with violating crystal iodine.
2) They may be flagellated or non-Flagellated. Flagellated bacteria can move while non- flagellated bavteria cannot move.
3) They base plasmid. The plasmid is present additionaly as a circular D.N.A. other than nucleotide.
4) In their cell membrane pili is present
5) From the characteristics mentioned above, it is seen that E. coli bacteria are more or less identical to the common bacteria.
They usually live in the intestines of vertebrates including human, A great deal of E coli bacteria come out with the faecal matter of the animal and can exist in water, soil and in food materials.