DNA Biology Practice Test

Both terms describe how foreign DNA gets into cells to drive gene expression, but they apply to different kinds of cells. In bacteria, transformation means the uptake of naked DNA from the surrounding environment by competent cells. Once inside, the DNA—often a plasmid—can be replicated and expressed using the bacterial transcription and translation machinery, and selective markers help identify cells that carry the new DNA. In contrast, introducing DNA into eukaryotic cells is called transfection. This delivery is usually achieved with methods like liposomes, electrical pulses, or viral vectors, and the DNA must reach the nucleus to be transcribed and translated by the cell’s machinery. Expression can be transient or, if the DNA integrates or a replicating vector is used, more stable. So, the difference hinges on the host organism and the delivery approach: transformation for bacteria, transfection for eukaryotic cells, with both ultimately aiming to get gene expression in the host.