What are plasmids?

In many different bacteria, small circular pieces of DNA can be found in the cytoplasm. These DNA circles are known as plasmids and are separated from chromosomal DNA or DNA, which bears genes for bacterial cells. Several copies of plasmids are often present at a bacterial cell at once. Plasmides play a very important role in genetic engineering, especially in gene cloning.

When genes are cloned, the process is usually in bacteria. In order to obtain a gene to be cloned in bacteria, a vector is required. Plasmid is what is used as a vector because it can easily pass from one cell to another.

There are a number of steps before plasmid insertion into the host cell. First, a gene to be copied, as well as the plasmides to be used as vectors, must be isolated. Upon completion, the gene must be inserted into the plasmid DNA. The plasmid is then inserted into the bacterieal host cell for replication.

For isolation of plasmids from bacterial cells must be cellsTKU treated enzymes to break the cell walls of bacteria. Larger chromosomal DNA is separated from smaller plasmids using a centrifuge. Isolated plasmid DNA is now ready for the gene to be inserted into it.

The

plasmids consist of a two -thirds circle of the bottom. To insert the desired gene, plasmide DNA is cut by restriction enzymes. These enzymes cut DNA only in very specific nucleotide sequences. Once the plasmid DNA is cut, the sequence of linkers is added to the free ends that correlate with the end of the gene to be inserted. This ensures that the gene fits exactly into the plasmid.

As soon as the gene is inserted into the plasmide, it is now ready to put into a living bacterium. Bacteria replicate their plasmids so that one cell can make many copies. There may be up to 200 copies of one plasmide within one bacterium. If the plasmide is introduced into many bacterial cells, it may be manyThe gene of the gene produced relatively fast, especially when bacterial cells are replicated every 20 minutes.

This is a process that is used to create human insulin. The insulin -coded gene was isolated and inserted into the plasmid. All plasmids containing the insulin gene were then introduced into bacteria where they were replicated. The bacteria were then replicated, so many millions of cells containing insulin genes can be created in a very short time. This cloned gene now provides a reliable source for human insulin.