## Friday, December 28, 2012

### Metric Prefixes and Scientific Notations

A metric prefix is a shorthand notation used to denote very large or vary small values of a basic unit as an alternative to expressing them as powers of 10. Basic units frequently used in the biological sciences include meters, grams, moles, and liters.Because of their simplicity, metric prefixes have found wide application in molecular biology. The following table lists the most frequently used prefixes and the values they represent.

Metric Prefix
1 nanogram (ng) is equivalent to 1*10^-9 grams. There are, therefore, 1*10^9 nanograms per gram (the reciprocal of 1*10^-9; 1/1*10^9 = 1*10^-9). Likewise, since one microliter (uL) is equivalent to 1*10^-6 liters, there are 1 x 10^6 uL per liter.

When expressing quantities with metric prefixes, the prefix is usually chosen so that the value can be written as a number greater than 1.0 but less than 1000. For example, it is conventional to express 0.00000005 grams as 50 ng rather than 0.05 ug or 50,000 pg.

Reference:
Mathematics in molecular biology and biotechnology