Biology Regents Practice Exam

What is a likely reason that certain bacteria are no longer affected by a chemical added to hand sanitizers and dish detergents?

1. They have slower metabolic rates

2. They have a mutation for resistance

3. They have been selectively bred for survival

4. They have an adaptation to a different niche

The correct answer is: They have a mutation for resistance

Bacteria that are no longer affected by certain chemicals in hand sanitizers and dish detergents likely possess mutations that enable them to resist these substances. Such mutations can alter the structures or functions of the bacterial cell membranes or enzymes, decreasing the effectiveness of the sanitizers and detergents. Over time, through the process of natural selection, these resistant bacteria can become more prevalent in a population, as they survive and reproduce in environments where these chemicals are used. This phenomenon can occur due to selective pressure imposed by the frequent use of these products, leading to a population that is increasingly composed of individuals with resistance traits. The presence of these mutations clearly explains the reduced effectiveness of certain antimicrobial agents against them.