GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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bacteriophages can infect bacteria
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the genetic material of the phage is DNA
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DNA is made of nucleotides
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the genetic material of the phage is protein
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Detailed explanation-1: -In an important experiment, a radioactively labeled bacteriophage was allowed to infect bacteria. In a first trial the page contained radioactive DNA, and the radioactivity was detected inside the bacteria. Next, phage containing radioactive protein was used, and the radioactivity was not detected inside the bacteria.
Detailed explanation-2: -Thus, the Hershey-Chase experiment helped confirm that DNA, not protein, is the genetic material. Hershey and Chase’s experiment concluded that little sulfur containing material entered the bacterial cell.
Detailed explanation-3: -They knew that bacteriophage T4 was made of protein and DNA. They also knew that proteins contain sulfur atoms but no phosphorus, while DNA contains a great deal of phosphorus and no sulfur. They used radioactive sulfur and phosphorus to label and, so, distinguish viral proteins from viral DNA.
Detailed explanation-4: -The researchers used different radioactive elements to label the DNA and proteins in viruses. This allowed them to identify which molecule the viruses inserted into bacteria. DNA was the molecule they identified. This confirmed that DNA is the genetic material.
Detailed explanation-5: -Conclusion: Resultant radioactive and non-radioactive bacteria infer that the viruses that had radioactive DNA transferred their DNA to the bacteria but viruses that had radioactive protein didn’t get transferred to the bacteria. Hence, DNA is the genetic material and not the protein.