In this article we will discuss about the meaning of transformation. Transformation is the process of adding a foreign DNA fragment from a donor genome into genome of a recipient cell. The donor fragment passes through the cell membrane of the recipient cell (which may or may not belong to the same species) and becomes incorporated into the latter's genome [...]
In this article we will discuss about the DNA replication in eukaryotes. In eukaryotes there are only two different types of DNA polymerases in contrast with DNA polymerase I, II and III of prokaryotes. Furthermore the DNA of eukaryotes is a long linear molecule with several replication units. A diploid mammalian cell contains on an average about 6 pg of [...]
The work of J. Cairns demonstrated DNA replication in bacteria in an elegant way. He used high resolution autoradiography for observing the distribution of radioactive label in the "chromosomes" of dividing E. coli cells. The bacterial cells were grown on a medium containing tritiated thymidine. The labelled DNA was extracted from the cells and spread on EM grids. A very [...]