Question

For the isolation of DNA, different lysing enzymes are used for breaking different cell types and constituents. Which among the following is not used while isolating DNA from bacteria?

• A. Protease
• B. Lysozyme
• C. Ribonuclease
• D. Deoxyribonuclease

Answer 1

The correct option is D Deoxyribonuclease

DNA is the hereditary material and information storage system in a cell. In prokaryotes, DNA is not enclosed within the nucleus. Bacterial cells do not have a nucleus and hence the genetic material of the bacteria lies free in the cytoplasm.
To isolate DNA from a cell, it is necessary to break open the cell and extract the DNA content of the cell along with other macromolecules of the cell. It is done by treating a cell with different enzymes according to the constituents of the membranes or macromolecules. For example enzymes like lysozyme for bacterial cell wall, cellulase for plant cell wall, chitinase for fungus cell wall etc.

RNA can be removed by treatment with ribonuclease and proteins can be broken down by enzyme proteases. There are various other treatments that are there to remove other molecules and purify DNA ultimately. But, if the enzyme deoxyribonuclease is used, then it will digest the purified DNA and the whole process of isolation of DNA will get spoiled.