Video Transcript
Which of the following can be used
as carriers of foreign genetic material in bacterial transformation? (A) Phages and prions. (B) Plasmids, phages, and
prions. (C) Plasmids and prions. (D) Plasmids.
Bacterial transformation is a
natural process used by some bacteria to take in foreign DNA found free in their
environment. This gives bacteria an evolutionary
advantage that helps them survive changes in their environment. The genome of bacteria is contained
in one long circular chromosome that floats freely in the cytoplasm. Bacteria can also contain small
circular DNA called plasmids. Bacteria use these plasmids to
easily exchange genetic material through a process called conjugation. But in transformation, bacteria
take up the plasmids found in the environment directly through their membrane.
Plasmids have their own origin of
replication, which allows plasmids to be replicated a large number of times
independently of the bacterial chromosome. This process allows DNA
cloning. Thanks to their properties,
plasmids are thus useful carriers of foreign genetic material into bacteria. In the lab, plasmids can be
specifically designed so that they contain a gene of interest isolated from a
different species. For example, the gene coding for
human insulin can be inserted in a plasmid. This recombinant plasmid is then
introduced into a bacterium by transformation. Recombinant bacteria can then
produce large quantities of human insulin.
Bacteriophages or, more simply
said, phages constitute another way that is commonly used in biotechnology to carry
foreign genetic material into bacteria. Phages are viruses that infect
bacteria. They can be used to carry genetic
material into bacteria. But phages inject their DNA by a
process called transduction, which is different from bacterial transformation.
Prions are misfolded proteins that
have infectious properties. Prions do not contain genetic
material and are not used for bacterial transformation.
We are now able to select the
correct answer, which is (D). Plasmids can be used as carriers of
foreign genetic material in bacterial transformation.
