Hyerin Yoo's List: Algebra

How do bacteria multiply?

 Bacteria multiply in a straightforward manner (apologies to molecular biologists for the simplification). Each single celled bacterium grows until there is enough material to form two separate bacteria. The one parent bacterium then splits into two progeny bacteria. This process is known as binary fission. The time that it takes one bacterium to accumulate enough material to split is known as the generation length. This generation length varies greatly between different genus and species of bacteria, from as short as twenty minutes for E. coli to as long as twenty four hours for Mycobacterium tuberculosis. The population growth curve for bacteria is an exponential curve. With each generation, the number of bacteria doubles. In ideal circumstances (i.e. a ready supply of nutrients and a benign environment), a single E. coli bacterium can grow to become over one million bacteria in as little as three and a half hours. For one Mycobacterium tuberculosis bacterium to generate the same number of bacteria, again under ideal circumstances, may take as long as ten days. 

 In practice, however, this is not always the case, since the circumstances in which bacteria grow are not always ideal. Nutrients may not be plentiful, the temperature may be too warm or too cold, the acidity of the environment may be too high or too low, there may be chemicals present which inhibit the growth of bacteria or there may be organisms present that consume and destroy bacteria.