isotope

(noun)

any of two or more forms of an element where the atoms have the same number of protons, but a different number of neutrons within their nuclei

Related Terms

Examples of isotope in the following topics:

  • Basics of DNA Replication

    • They grew E. coli for several generations in a medium containing a "heavy" isotope of nitrogen (15N) that is incorporated into nitrogenous bases and, eventually, into the DNA .
    • The E. coli culture was then shifted into medium containing the common "light" isotope of nitrogen (14N) and allowed to grow for one generation.
    • So DNA grown in 15N had a higher density, as would be expected of a molecule with a heavier isotope of nitrogen incorporated into its nitrogenous bases.

  • Biological Magnification

    • Numbers on the x-axis reflect enrichment with heavy isotopes of nitrogen (15N), which is a marker for increasing trophic levels.

  • Evidence of Global Climate Change

    • Temperatures relative to the present are determined from the amount of deuterium (an isotope of hydrogen) present.

  • Carbon Dating and Estimating Fossil Age

    • Radiometric dating is a technique used to date materials such as rocks or carbon, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.