Why length of bacteria is 3-5um and that of typical bacteria is 0.1um ?
Answers
Answer: In general, bacteria are between 0.2 and 2.0 um - the average size of most bacteria. Research studies have shown their size to play an important role in survival over time.
Due to their small size, bacteria are able to exploit and thrive in various microenvironments. These include such environments as the vertical gradients in intertidal marine sediments in which various types of bacteria have been found. Because various microorganisms are absent in such environments, bacteria successfully exploit resources available and thrive in such environments.
The small size of bacteria is also beneficial for parasitism and oligotrophy. Bacteria can continue relying on a range of hosts (large and small) for their nutrition. In addition, they can also live and survive in environments that contain a low concentration of nutrients; for instance, a group of bacteria known as oligotrophic bacteria.
Bacteria have a high surface area to volume ratio that allows them to take up as many nutrients as possible for survival. In the process, they are able to continue growing and reproducing at a stAGE.
In bacteriology, the micron (micrometer) is the primary unit of measurement: I micrometer (um) is one-thousandth of a millimeter.
* Given that the limit of resolution for a human eye (naked eye) is between 100 and 200 um (about the diameter of a human hair) then the majority of bacteria cannot be seen with the naked eye.