Hershey and Chase carried their experiment in three steps : infection, blending, centrifugation. Explain each step.

Question

(a) Hershey and Chase carried their experiment in three steps : infection, blending, centrifugation. Explain each step.
(b) Write the conclusion and interpretation of the result they obtained.

Answer 1

(a) • Infection - Radioactive phosphorus / phosphorus labelled bacteriophages were allowed to infect E.coli - growing in a culture medium,simultaneously radioactive sulphur / sulphur labelled bacteriophage was allowed to infect E.coli growing in another culture medium
• Blending- As infection proceeds- the viral coats are removed from the bacteria by agitating in a blender

• Centrifugation - virus particles were seperated from bacteria by spinning them in a centrifuge 
(b) Conclusion - DNA is the genetic material  Interpretation - sulphur labelled viral protein did not enter the bacteria during infection , whereas phosphorus labelled viral DNA entered into the bacteria to cause infection