|Davis, Dulbecco, Eisen, Ginsberg, Bacterial Physiology: Microbiology, Second Edition, Maryland: Harper and Row, 1973: 96-97.||"Turbidity is linear with bacterial density between 0.01 mg dry weight (ca. 107 cells) and 0.5 mg/mL."||1 × 10−12 g|
|Evolution, Microbial Life, and the Biosphere [pdf]. BISC 300,University of Southern California, Fall 2002.||"Mass of one bacterium: 9.5 × 10−13 g"||9.5 × 10−13 g|
|Tanner, Shape and Size of Bacterial Cells: Bacteriology, Fourth Edition, New York: John Wiley & Sons, Inc., 1948: 78-79.||"Kendell has stated that 1,600,000,000 cells of Escherichia coli would weigh a gram."||6.25 × 10−10 g|
|Material and Materials II [pdf]. Massachusetts Institute of Technology, 20 February 2003||"Assuming that the cantilever has been covered by nb = 100 bacterium cells, each of mass mb = 3 × 10−4 pg (note: 1 pg = 10−12 g), evaluate the change in natural frequency that you can expect to see for the cantilever."||3 × 10−16 g|
Bacteria are single-sell organisms that are quite simple. They are one of the earliest forms of life that appeared on Earth billions of years ago. They and archaea belong to a category of life called Prokaryotes. All other forms of life belong to Eukaryotes. Prokaryote's genetic material, better known as DNA, is not in a cellular structure called the nucleus. Eukaryotic cells do have nuclei. Generally the masses vary between different types of bacterium. A typical mass of a bacterium would be about 10−12 g or one picogram (pm).
Bacteria live in a wide range of environments. They can exist in extremely hot and extremely cold climates. Although there are thousands of species of bacteria, all of them are one of three basic shapes. Some are shaped like sticks or rods, called bacilli. Other are shaped as little balls and called cocci. Still others have a helical or spiral shape, called spirochetes. Some forms of bacteria exist as individual bacterium while others group together to form pairs, chains, and other connected structures.
Bacteria are found on every material and habitat on this planet. There are about 100,000 bacterium cells on each square inch of your skin and over a billion bacteria in a spoonful of soil!!!
Louis Siu -- 2003