| hershey-chase experiment | <molecular biology> A landmark experiment done in 1952 which showed that DNA is the hereditary material. The experiment, done by Martha Hershey and Alfred Chase, involved allowing a bacteriophage which contained DNA labelled with 32P (an isotope of phosphorus) and a protein labelled with 35S (an isotope of sulphur) to attach to some bacteria. When the bacteriophages were later removed, they found that it was the 32P (and thus the DNA) that had entered the bacterial cells rather than the 35S (indicating the protein). (09 Oct 1997) |
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| pulse chase | <biochemistry> An experimental protocol used to determine cellular pathways, such as precursor product relationships. A sample organism, cell or cellular organelle), is exposed for a relatively brief time to a radioactively labelled molecule, the pulse. It is then replaced with an excess of the unlabelled molecule, the chase (cold chase). The sample is then examined at various later times to determine the fate of radioactivity incorporated during the pulse. (15 Dec 1997) |
| pulse-chase experiment | An experiment in which an enzyme, a metabolic pathway, a culture of cells, etc., interacts with a brief addition (pulse) of a labelled compound followed by its removal and replacement (chase) by an excess of unlabelled compound. (05 Mar 2000) |