Answer the following questions based on Hershey and Chases’s experim

1.	Answer the following questions based on Hershey and Chases’s experiments: a. Name the kind of virus they worked with and why? b. Why did they use two types of culture media to grow viruses in? Explain. c. What was the need for using a blender and later a centrifuge during their experiments? d. State the conclusion drawn by them after the experiments.
Answer» a. They worked with bacteriophage because when it attacks a bacteria it only inserts its genetic material in its body. b. They grew some viruses on a medium that contained radioactive phosphorus and some others on medium that contained radioactive sulphur. Viruses grown in the presence of radioactive phosphorus contained radioactive DNA but not radioactive protein because DNA contains phosphorus but protein does not. Similarly, viruses grown on radioactive sulphur contained radioactive protein but not radioactive DNA because DNA does not contain sulphur. c. Blender was used to agitate the bacteria to remove the viral coats from them. Centrifuge was used to separate virus particle from the bacteria. d. Bacteria which was infected with viruses that had radioactive DNA were radioactive, indicating that DNA was the material that passed from the virus to the bacteria. Bacteria that were infected with viruses that had radioactive proteins were not radioactive. This indicates that proteins did not enter the bacteria from the viruses. DNA is therefore the genetic material that is passed from virus to bacteria.

Answer the following questions based on Hershey and Chases’s experiments: a. Name the kind of virus they worked with and why? b. Why did they use two types of culture media to grow viruses in? Explain. c. What was the need for using a blender and later a centrifuge during their experiments? d. State the conclusion drawn by them after the experiments.

Answer»

a. They worked with bacteriophage because when it attacks a bacteria it only inserts its genetic material in its body.

b. They grew some viruses on a medium that contained radioactive phosphorus and some others on medium that contained radioactive sulphur. Viruses grown in the presence of radioactive phosphorus contained radioactive DNA but not radioactive protein because DNA contains phosphorus but protein does not. Similarly, viruses grown on radioactive sulphur contained radioactive protein but not radioactive DNA because DNA does not contain sulphur.

c. Blender was used to agitate the bacteria to remove the viral coats from them. Centrifuge was used to separate virus particle from the bacteria.

d. Bacteria which was infected with viruses that had radioactive DNA were radioactive, indicating that DNA was the material that passed from the virus to the bacteria. Bacteria that were infected with viruses that had radioactive proteins were not radioactive. This indicates that proteins did not enter the bacteria from the viruses. DNA is therefore the genetic material that is passed from virus to bacteria.

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