Cell Biology: DNA and Viruses
1. Bacteriophage M13 infects E. coli differently from the way bacteriophage T2 does. The M13 coat is removed in the inner membrane of the bacterial cell, where it is sequestered during phage replication. It is subsequently used to package the newly replicated phage DNA to create progeny phage. Why would this make M13 less suitable than T2 for the Hershey and Chase experiment?
2. Adenovirus has a double-stranded linear DNA genome that measures 12.2 m in length. How many base pairs make up the adenovirus genome?
3. A DNA is found to exhibit a melting point of 75C in 0.1 M NaCl. What effect would each of the following have on the malting point of the DNA?
a. Increased NaCl
b. Decreased DNA concentration
c. Adding 1% formamide
...ioactively labeled DNA with 32P and protein with 35S separately in differently T2 phage. They infected E.coli with each phage, after infection they removed the empty phage by a blender. Then they examined which radioactively labeled component entered the cell: The DNA or the protein?
Result: Upon infection most DNA entered the cell while the protein did not
Conclusion: The T2 bacteriophage carries its genes and heredity information in its DNA.
Now as your questions outline M13 differs from T2 in that its coat is removed in the inner membrane of the bacterial cells and is sequestered during phage replication. The protein from the T2 phage never enters the cell, but the protein from M13 does. So if the Hershey-Chase experiment ...