Microbiology Practice Exam

What term describes a cell that is permeable to foreign DNA?

1. Transgenic

2. Competent

3. Mutated

4. Primary

The correct answer is: Competent

The term that describes a cell that is permeable to foreign DNA is "competent." Competence refers to the ability of a bacterial cell to take up extracellular DNA from its environment. This natural phenomenon is an important aspect of horizontal gene transfer allowing bacteria to acquire new genetic material, which can lead to various beneficial traits, such as antibiotic resistance or the ability to utilize new substrates. Competent cells possess specific mechanisms that facilitate the intake of DNA, which may involve changes in the cell wall and membrane that increase their permeability. This property is often exploited in molecular biology and genetic engineering, where scientists can introduce plasmids or other DNA into competent cells to produce recombinant proteins or to study gene function. In contrast, transgenic refers to organisms that have been genetically altered to contain genes from other species. Mutated describes cells that have undergone a change in their DNA sequence, which does not inherently indicate their ability to take up foreign DNA. Primary generally refers to primary cell lines or cultures that are derived directly from living tissues and does not specifically relate to DNA uptake. Therefore, competent is the most accurate term describing a cell's ability to take in foreign DNA.