Read the given paragraph carefully and answer the following questions:

Since the DNA is enclosed within the membranes, we have to break the cell open to release DNA along with other macromolecules such as RNA proteins, polysaccharides and also lipids. This can be achieved by treating the bacterial cells/plant or animal tissue with enzymes such as lysozyme (bacteria), cellulase (plant cells), chitinase (fungus). There are some basic steps. in genetically modifying an organism-identification of DNA with desirable genes: (i) introduction of the identified DNA into the host; (iii) maintenance of introduced DNA in the host and transfer of the DNA to its progeny. Agrobacterium tumifaciens, a pathogen of several dicot plants is able to deliver a piece of DNA known as 'T-DNA' to transform normal plant cells into a tumor and direct these tumor cells to produce the chemicals required by the pathogen. Other molecules can be removed by appropriate treatments and purified DNA ultimately precipitates out after the addition of chilled ethanol. Selection of recombinants due to inactivation of antibiotics is a cumbersome procedure because it requires simultaneous plating on two plates having different antibiotics. Therefore, alternative selectable markers have been developed which differentiate recombinants from non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme, β-galactosidase. This results into inactivation of the gene for synthesis of this enzyme, which is referred to as insertional inactivation.

Which enzyme is not used to lyse the cells for extraction of DNA?

Protease

The correct answer is Option (3) → Protease  

The enzyme not typically used to lyse cells for DNA extraction is protease.

 To extract DNA, you first need to break open the cell membrane and cell wall (if present). This process is called cell lysis.

• Lysozyme: This enzyme is used to break down the peptidoglycan in the cell walls of bacteria, making it a key component for lysing bacterial cells.

• Cellulase: This enzyme is used to break down the cellulose in the cell walls of plant cells.

• Chitinase: This enzyme breaks down chitin, a major component of the cell walls of fungi and the exoskeletons of arthropods.

Protease is not primarily used for cell lysis. Instead, its main function in DNA extraction is to degrade proteins, including histones that are tightly bound to the DNA, and nucleases that can degrade the DNA itself. Protease is used after the cells have been lysed to purify the DNA from unwanted proteins, ensuring the final DNA sample is clean and intact.