A researcher is attempting to isolate pure DNA from a bacterial culture. Which of the following pairs of enzymes should be used to first break open the bacterial cells and subsequently remove the contaminating RNA from the resulting mixture?

Step-by-step solution

To isolate DNA from bacterial cells, the bacterial cell wall must be degraded using the enzyme lysozyme. During the subsequent purification process, contaminating RNA is removed by treating the mixture with ribonuclease (RNase). Protease is used to remove proteins, not RNA. DNase is strictly avoided because it would destroy the target DNA molecule itself. Cellulase is used to break open plant cells, not bacterial cells. Answer: Lysozyme and Ribonuclease