Florida Biology EOC Practice Test

Why are antibiotics not effective against viruses?

1. They can't differentiate between bacteria and viruses

2. Viruses lack the structures that antibiotics target

3. Viruses are too small for antibiotics to affect

4. They were developed only for bacterial diseases

The correct answer is: Viruses lack the structures that antibiotics target

Antibiotics are designed to target specific structures and functions that are present in bacteria but absent in viruses. This fundamental difference lies in the biology of the two types of organisms. Bacteria are living cells that possess cellular machinery, cell walls, and specific metabolic pathways that antibiotics can disrupt. For instance, some antibiotics target bacterial cell walls, interfere with protein synthesis, or inhibit DNA replication. Viruses, on the other hand, are fundamentally different; they are not considered living organisms. They are composed of genetic material (either DNA or RNA) encapsulated in a protein coat, and they rely on host cells to replicate and carry out metabolic processes. Because of this reliance, viruses do not have the cellular structures that antibiotics can target, rendering these medications ineffective against viral infections. The other options do not accurately capture the reason for the lack of effectiveness of antibiotics against viruses. While antibiotics may not differentiate between types of microorganisms, their primary ineffectiveness stems from the absence of the necessary structures in viruses. Moreover, the size of viruses in comparison to bacteria does not contribute to antibiotic resistance, and while it's true that most antibiotics were developed for bacterial infections, this does not explain why they are ineffective against viruses.