AP BIOLOGY

Detailed explanation-1: -A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA. Plasmids naturally exist in bacterial cells, and they also occur in some eukaryotes. Often, the genes carried in plasmids provide bacteria with genetic advantages, such as antibiotic resistance.

Detailed explanation-2: -Eukaryotic expression plasmids were introduced into the nucleus of host cells following lysis of the intracytosolic, plasmid-carrying bacteria with antibiotics. Cell lines of different tissues and species could be transfected in this way.

Detailed explanation-3: -Plasmids have been key to the development of molecular biotechnology. They act as delivery vehicles, or vectors, to introduce foreign DNA into bacteria. Using plasmids for DNA delivery began in the 1970s when DNA from other organisms was first ‘cut and pasted’ into specific sites within the plasmid DNA.

Detailed explanation-4: -Plasmids are found in eukaryotes are the same that is found in prokaryotes. Plasmids refer to extrachromosomal free circular DNA found in the cytoplasm. Irrespective of the organism the structure or the typical nature of the plasmid does not undergo any major change.

Detailed explanation-5: -Most bacteria do not take up a plasmid, but some do. Plasmids used in cloning contain an antibiotic resistance gene. Thus, all of the bacteria are placed on an antibiotic plate to select for ones that took up a plasmid.