Question

Plasmids are small circular DNA molecules found in bacteria that replicate separately from chromosomes. Why are plasmids essential for recombinant DNA technology? Plasmids are able to rapidly reproduce exact copies of cells, so they provide a means to acquire a large number of cells that contain a particular gene of interest. DNA from a gene of interest can be inserted into a plasmid, then the modified plasmid can be inserted into a bacterial cell to replicate a gene of interest many times. Plasmids can cleave the sugar–phosphate bonds in DNA molecules in a staggered manner, creating single‑stranded, "sticky" ends of DNA where the gene of interest can attach. Plasmids provide the catalytic action required to denature a molecule of DNA from a gene of interest that can be used in recombinant DNA technology.

Answer 1

Plasmids are crucial in recombinant DNA technology as vectors that can carry foreign DNA into bacterial cells for replication and expression, utilizing restriction endonucleases to insert genes of interest.

Step-by-step explanation:

Plasmids are essential for recombinant DNA technology because they can be used as vectors to introduce foreign DNA into bacterial cells, where the DNA can be replicated and expressed. These small, circular DNA molecules replicate independently from the chromosome and are often engineered with a multiple cloning site (MCS) that contains several sites for restriction endonucleases to act. These enzymes make precise cuts in DNA, producing 'sticky ends' that can be joined to complementary sequences on the inserted gene fragment. Once the gene of interest is inserted, the plasmid can be introduced into bacteria to mass-produce the gene or the protein it encodes.

Answer 2

DNA from a gene of interest can be inserted into a plasmid, then the modified plasmid can be inserted into a bacterial cell to replicate a gene of interest many times.

Step-by-step explanation:

Plasmids are the extra-chromosomal circular DNA present in bacterial cells. Plasmids are able to replicate themselves independent of genetic DNA. Their ability to self replicate allows them to maintain themselves in the bacterial cells. This is why plasmids are used as cloning vectors in recombinant DNA technology.

A gene of interest is isolated from the donor cell and is inserted into the plasmid. The recombinant plasmid is introduced into bacterial cells where it replicates the ligated desired gene and allows the gene cloning. For example, the human insulin gene is ligated with plasmid and the recombinant plasmid is introduced in E. coli where it replicates the human insulin gene and allows the production of desired copies of the gene.