What are plasmids?Plasmids are DNA molecules that are used formany purposes including carrying genes fromorganism to organism, making copies of genes,and transporting genes to sites in gene therapy.
What types of plasmids are there? There are 3 types1. Conjugative plasmids: Able to perform conjugation, which is the process of transferring plasmids to another environment2. Non-conjugative plasmids: Unable to perform conjugation3. Intermediate plasmids: Able to be transferred by conjugative plasmids. They contain a subset of genes
Functions of plasmids There are 5 main classes1. Fertility plasmids: can perform conjugation2. Resistance plasmids: contain genes that build a resistance against antibiotics or poisons3. Col plasmids: contain genes that code for proteins that can kill bacteria4. Degradative plasmids: enable digestion of unusual substances5. Virulence plasmids: turn the host of the plasmid into a pathogen
Shapes of plasmids There are 5 shapes of plasmids1. Nicked Open-Circular: DNA has one strand cut2. Relaxed Circular: DNA is fully intact3. Linear: DNA has free ends4. Supercoiled: DNA is fully intact but has a twist in it, making it more compact5. Supercoiled Denatured: Slightly less compact than supercoiled
Plasmids in genetic engineeringIn genetic engineering, plasmids are used tomake copies of particular genes. This is done byinserting the gene to be replicated into theplasmid, then inserting the plasmids intobacteria by a process called “Transformation”.Next the bacteria are exposed to antibiotics thatdestroy bacteria without the plasmid. Thesebacteria are then grown in large amounts withtheir new genes.
Plasmids in gene therapyIn gene therapy, plasmids are used to deliver thetherapeutic genes to the selected chromosomalsite.
Plasmid partsA vector is a DNA molecule used to carry genesfrom organism to organism. Plasmids have 3key parts. They have an origin of replication, aselectable marker gene, and a cloning site. Theorigin of replication is used to indicate whereDNA replication is to begin. The selectablemarker gene is used to distinguish cellscontaining the plasmid from cells that don’tcontain it. The cloning site is a site in theplasmid where the DNA is inserted.
ConclusionIn conclusion, a plasmid is a DNA molecule that is used for a variety ofpurposes, such as making copies of particular genes, delivering genesto specific locations and many more. While they may sound likesomething from science fiction, they are used by scientists around theworld and can be invaluable.