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Radioactive isotopes! please read

  1. Mar 24, 2004 #1
    5. Radioactive and heavy isotopes can be used to label biochemical molecules. Describe how their use has enabled scientists to understand biochemical pathways and processes.

    Can anyone direct me to any decent websites that might give some info related to this?
    Thanks for your help.
  2. jcsd
  3. Mar 24, 2004 #2
    You could start by looking up the Hershey-Chase Experiment. It was an early study done to provide support for DNA as the info for life.

  4. Mar 24, 2004 #3


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    Hi Geordie, think for instance about characterizing the length of time it takes for a cell to go through the different phases of mitosis. By addition of 3H-thymidine you can analyze the rate at which this radioactive base is incorporated in the DNA during the synthesis phase.

    But the use of radioactive compounds is becoming an old technique. Now there is a wide range of fluorescent compounds that can be used (although they are generally more expensive). Fluorescence has the technical advantage that it can be quenched, thus leading to new applications. Quenching means silencing the fluorescence.. for an application think about showing that two molecules undergo physical interaction.. if the molecules are apart there will be fluorescence, if they are in close proximity fluorescence will diminish.
  5. Mar 24, 2004 #4
    Something else that may be of interest.

    Stable (non-radioactive) isotopes are also quite useful since you can track the process of incorporation and metabolism via mass spectrometry. So if you expect that if you feed an organism a labeled compound and that it would eventually fully incorporate into a metabolite, you should be able to see that on a mass spectrograph with the m/z ratio increasing. With the advances in mass spectrometry - most notably sensitivity and resolution - in the recent past, it's becoming an incredibly useful analytical technique.
  6. Mar 25, 2004 #5


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    Or how about cell biology where you pulse label certain molecules and follow them how they proceed through the ER and Golgi apparatus etc
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