Phage Lab Report
Phage is a virus that consists of a protein coat that surrounds the core of DNA. When phage DNA enters the host cell it directs phage reproduction. DNA is the molecule that is responsibility for heredity. In this experiment, phage was added to E.coli in a radioactive medium. Phages were used to demonstrate that DNA is the genetic material. The DNA molecule is surrounded by a protein coat. So, when phages infect bacteria, they will attach to the surface of the bacterium. When this happens, they inject DNA into the cell. The protein coat remained on the outside of the cell.
The phages were produced in a radioactive medium that resulted in a phage population with Sulfur labeled proteins. There was no radioactive label in this DNA. The phages
were then allowed to infect the bacteria. Then the phages attached to the bacterial cells and injected their DNA. The radioactively labeled protein coat remained on the outside of the cell. The phage produced contained no radioactivity. The vigorous shaking then caused the empty protein coats to be removed. This did not interfere with the production of the new phage in the cell. In the next part of this experiment, the phages were produced in a medium containing phosphorus labeled deoxyribonucleotides. This resulted in a phage population with Phosphorous labeled DNA. There were no radioactive labels in the protein. When the phage infected the bacteria, the Phosphorous labeled DNA entered the cell and could be found in the phage. This showed that the DNA, not the protein carries the genetic information for a new generation of phage.
The phages were produced in a radioactive medium that resulted in a phage population with Sulfur labeled proteins. There was no radioactive label in this DNA. The phages
were then allowed to infect the bacteria. Then the phages attached to the bacterial cells and injected their DNA. The radioactively labeled protein coat remained on the outside of the cell. The phage produced contained no radioactivity. The vigorous shaking then caused the empty protein coats to be removed. This did not interfere with the production of the new phage in the cell. In the next part of this experiment, the phages were produced in a medium containing phosphorus labeled deoxyribonucleotides. This resulted in a phage population with Phosphorous labeled DNA. There were no radioactive labels in the protein. When the phage infected the bacteria, the Phosphorous labeled DNA entered the cell and could be found in the phage. This showed that the DNA, not the protein carries the genetic information for a new generation of phage.