why do scientists use the same enzyme to remove the insulin and cut the plasmid?

Scientists use the same enzyme, typically a restriction enzyme, to remove the insulin gene from its original source and to cut the plasmid for gene insertion mainly for convenience and efficiency purposes.

Restriction enzymes are molecular scissors that can recognize specific DNA sequences and cut the DNA at those sites. These enzymes are naturally found in bacteria as a defense mechanism against viruses. They cleave the DNA at specific sequences, leaving behind sticky or blunt ends, depending on the enzyme used.

When scientists want to remove the insulin gene from its original source, they isolate the DNA containing the insulin gene, along with other surrounding DNA fragments. To specifically extract the insulin gene, they use a restriction enzyme that recognizes a unique sequence within the DNA region where the gene is located. By cutting the DNA at this specific site, they can isolate the desired gene fragment.

Similarly, when scientists want to insert the insulin gene into a plasmid (a small, circular DNA molecule), they need to create a cut or a "vector" in the plasmid that will accommodate the insulin gene. To achieve this, they use the same restriction enzyme to digest the selected plasmid DNA. The enzyme will recognize and cut the plasmid at a specific DNA sequence, creating an opening for the insertion of the insulin gene.

Using the same enzyme for both processes maximizes efficiency and simplifies the experimental procedure. Scientists do not have to work with multiple enzymes, reducing the risk of errors and the time required for optimization. Moreover, using a single enzyme ensures compatibility between the cohesive ends generated from the digestion of both the insulin gene and the plasmid, facilitating subsequent steps in gene manipulation, such as gene insertion.

In summary, scientists use the same enzyme to remove the insulin gene and cut the plasmid for gene insertion to simplify and streamline the experimental process, ensuring compatibility between the DNA fragments and maximizing efficiency.