Plasmids | Genetics | Biology

bacteria have been helpful to genetic engineers not only in providing them with restriction enzymes but also with what are called plasmids in addition to their single chromosome many bacteria also contain tiny rings of DNA called plasmids plasmids are usually about one thousand to a hundred thousand nucleotides long and act as independent self-replicating molecular operators within bacterial plasmids are one of the ways that DNA recombination goes on within nature while the bacteria's chromosome contains all the necessary genes to code for the bacterias existence plasmids provide an effective way by which traits not contained in the chromosome can be passed from bacteria to bacteria for example some plasmids contain genes that code for enzymes that digest certain antibiotics such as penicillin or ampicillin this is obviously an advantage to the bacteria when a bacteria containing these plasmids dies it breaks open and liberates these plasmids to the outside environment and they are often taken up by other bacteria that then acquire the traits coded for by the plasmids genetic engineers can place liberated plasmids in a solution with restriction enzymes and cut them apart the engineers then place the genes segment they wish to insert into the solution with the plasmids and then add repair enzymes that join the pieces of DNA together at their sticky ends these new plasmids with their newly inserted genes are then placed with bacteria into a different solution that enables the plasmids to readily penetrate through the cell wall and membrane of bacteria the bacteria that are exposed to the plasmids are taken out and grown in a culture for a short time if the plasmids into which the experimental gene such as the gene for the production of insulin a growth hormone is inserted also have genes that provide resistance to ampicillin and amoxicillin a unique technique can be used genetic engineers know that not all the bacteria exposed to the plasmids will absorb them by exposing the cultured bacteria to antibiotics such as a pasilla nana mock Sicilian they kill off the bacteria that didn't absorb the new plasmids while those bacteria that did absorb the new plasmids containing the genes for antibiotic resistance and for say insulin or growth hormone continue to grow and thrive in the culture scientists continue to grow these bacteria until the insulin or growth hormone produced by them is sufficient to be extracted and purified for use by human patients but how our genes inserted into the chromosomes and DNA of more complex organisms such as plants or animals there are two major methods of placing DNA into the nuclei of eukaryotic cells vector 'less and vector methods vector 'less methods of insertion of DNA don't require the use of a third intermediate organism to deliver the DNA from one species to another vectors in the biological sense of the word are organisms that carry the DNA one species and insert it into another

Channel: greatpacificmedia

Views: 312,296

Keywords: Biotechnology, Plasmids, bacteria, genetic, engineer, restriction, enzymes, chromosomes, DNA, recombination, genes, penicillin, ampicillin, repair, culture, insulin, vectorless, vectors, genetics, biology

Id: GNMJBMtKKWU

Length: 4min 14sec (254 seconds)

Published: Fri Oct 23 2009