Biology - Molecular Basis of Inheritance Question with Solution | TestHub
E.colicells infected with bacteriophages having radioactive sulphur are grown in medium containing normal 'P' and 'S' after removing viral coats with the help of a centrifuge. The supernatant will show
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Answer:
Solution:
Bacteriophages with radioactive sulphur have their protein coats labelled with radioactive sulphur, while their DNA contains normal phosphorus.
During infection, only the viral DNA enters the E. coli cells. The radioactive protein coats remain outside and are separated from the cells by centrifugation.
The infected E. coli cells, which now contain viral DNA with normal phosphorus, are transferred and grown in a medium containing normal phosphorus and normal sulphur.
The progeny bacteriophages synthesized inside the host cells will utilize the nutrients from this new medium. Since both the medium and the parental viral DNA contain only normal isotopes, the newly formed bacteriophages will incorporate normal sulphur and normal phosphorus.
Upon lysis of the E. coli cells, these progeny bacteriophages are released into the medium. Therefore, the supernatant will show both normal sulphur and normal phosphorus.
Answer: both sulphur and phosphorus normal
