Question

Microbiology question. Please help.

DNA TRANSFER. When you combine Bacteria Z and Solution X, Bacteria Z gains new genes. In order to figure out what is happening, you manipulate Solution X, wait an hour and add it to Bacteria Z. First you add DNase to Solution X and the DNA still transfers. Then you use a 0.2 um filter on solution X and the DNA still transfers. Finally, you add proteinase to solution X and the transfer stops.

What DNA transfer process are you testing for at each step?

Adding DNase:

Filtering at 0.2um:

Adding Proteinase:

What is the process that is occurring here?

Answer 1

Answer:

There are few ways a bacteria obtain a foreign DNA

• Transformation-uptake and expression of foreign genetic material (DNA or RNA

• Transduction-bacterial DNA is moved from one bacterium to another by a virus (a bacteriophage, or phage)

• Bacterial conjugation- involves the transfer of DNA via a plasmid from a donor bacterial cell to a recombinant recipient cell during cell-to-cell contact.

Adding DNase: We would be testing for transformation

Filtering at 0.2um: Bacteria are filtered by 0.2 micron filters, hence the solution will be free of bacteria, here we are testing the possibility of Bacterial conjugation.

Adding Proteinase: Viruses are 100 times smaller than bacteria. Bacteriophages have DNA and a protein envelope and a around it. Protein envelope is necessary for the bacteriophage to attach itself to the bacteria and transfer the genetic material into it. Proteinase would digest the protein envelope. here we are testing the possibility of Transduction

What is the process that is occurring here?

Transduction-bacterial DNA is moved from one bacterium to another by a virus (a bacteriophage, or phage)