Transformation in bacteria refers to which process?

• A. Bacteria exchanging plasmids through a pilus
• B. Bacteria picking up and using genetic information from the environment
• C. Bacteria combining with viruses to transfer genes
• D. Bacteria mutating spontaneously

Answer: (B)

Transformation is the uptake of naked DNA from the surrounding environment by bacteria, followed by its incorporation into the cell’s genome or maintenance as a plasmid. Some bacteria are naturally competent or can be made competent in the lab to take up external DNA, which can come from lysed cells or purified DNA. This process relies on external DNA being acquired rather than DNA being transferred directly from one cell to another. That distinguishes it from conjugation, where DNA is moved between cells via a pilus, and transduction, where a bacteriophage carries DNA from one bacterium to another. Spontaneous mutation, on the other hand, is a change in the organism’s own DNA that occurs without uptake of external DNA.