Salt has a molar mass of 58.44 g/mol, glucose of 180.15 g/mol. 50 grams of glucose results in 278 millimoles of glucose. 9 g of sodium chloride correspond to 154 millimoles of sodium chloride. The osmolarity of the solution of sodium chloride, however, is 308 milliosmoles / liter.
In the natural world DNA usually becomes available by death and lysis of other cells, but in the laboratory it is provided by the researcher, often as a genetically engineered fragment or plasmid. During uptake, DNA is transported across the cell membrane(s) , and the cell wall if one is present.
pBR322 was one of the first plasmids used for the purpose of cloning. It contains genes for the resistance to tetracycline and ampicillin. Insertion of the DNA at specific restriction sites can inactivate the gene for tetracycline (an effect known as an insertional inactivation) or ampicillin resistance.owever, plasmids are not limited to bacteria; they are also present in some eukaryotes (e.g., circular, nuclear plasmids in Dictyostelium purpureum). A plasmid is a circular, double stranded DNA that is usually found in bacteria (however it does occur in both eukarya and prokarya).