Microbiology Lab Practical Practice Exam

The main idea here is synergy: two drugs working together produce a stronger antibacterial effect than either would alone. This means the combined kill or inhibition is greater than the sum of what each drug achieves separately. Synergy often happens when the drugs attack different targets or one drug helps the other penetrate the bacterial cell or overcome defenses. In the lab, you might observe this as a larger zone of inhibition or a lower MIC when both drugs are used together, and tests like checkerboard assays quantify this with a result indicating synergy. The other terms listed aren’t about drug interactions (for example, universal donor/receiver are blood transfusion terms, and DNA extraction is a lab technique), so they don’t describe two drugs working together to kill bacteria.