(a) Hershey and Chase carried their experiment in three steps : infect

1.	(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» (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

(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»

(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

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