Question

There are several methods by which genetic material can be exchanged between bacteria. Which of the following terms describes the uptake of DNA from the environment by the host cell? transduction transformation conjugation transfection

Answer 1

In transformation, a prokaryote takes in DNA from its environment shed by other prokaryotes. In transduction, bacteriophages move short pieces of chromosomal DNA between bacteria. In conjugation, DNA is transferred between prokaryotes via a pilus.

Step-by-step explanation:

In transformation, the prokaryote takes in DNA shed by other prokaryotes into its environment. If a nonpathogenic bacterium takes up DNA for a toxin gene from a pathogen and incorporates the new DNA into its own chromosome, it too may become pathogenic. In transduction, bacteriophages, the viruses that infect bacteria, may move short pieces of chromosomal DNA from one bacterium to another. Transduction results in a recombinant organism. In conjugation, DNA is transferred from one prokaryote to another by means of a pilus, which brings the organisms into contact with one another, and provides a channel for transfer of DNA. The DNA transferred can be in the form of a plasmid or as a composite molecule, containing both plasmid and chromosomal DNA. These three processes of DNA exchange are shown in Figure 22.17.

If a nonpathogenic bacterium takes up DNA for a toxin gene from a pathogen and incorporates the new DNA into its own chromosome, it too may become pathogenic. In transduction, bacteriophages, the viruses that infect bacteria, may move short pieces of chromosomal DNA from one bacterium to another. Transduction results in a recombinant organism. In conjugation, DNA is transferred from one prokaryote to another by means of a pilus, which brings the organisms into contact with one another, and provides a channel for transfer of DNA.