Many bacteria are now resistant to penicillin, because:

Question

Question

Penicillin causes gene mutations, some of which are beneficial
Previously resistant forms survived and reproduced better than non-resistance forms
The hospital environment inhibits competitions among bacteria
Penicillin triggers the synthesis of resistant proteins

Answer 1

Correct Answer: Previously resistant forms survived and reproduced better than non-resistant forms

Rationale:

Bacteria can develop resistance to antibiotics, such as penicillin, through the process of natural selection. When penicillin is used, it kills susceptible bacteria, but resistant bacteria survive and reproduce.
These resistant bacteria then pass on their resistance genes to their offspring, leading to a population of bacteria that is increasingly resistant to the antibiotic.
This phenomenon is a result of selective pressure, where the antibiotic acts as a selection agent, favoring the survival of resistant strains over non-resistant ones.

Explanation of Other Options:

Penicillin causes gene mutations, some of which are beneficial

Rationale: Penicillin itself does not cause gene mutations. Mutations occur spontaneously and randomly in bacterial populations. Some of these mutations may confer resistance, but it is not the antibiotic that directly causes these changes.

The hospital environment inhibits competition among bacteria

Rationale: The hospital environment does not inhibit competition among bacteria. In fact, hospitals can be hotspots for the spread of resistant bacteria due to high antibiotic use and the close proximity of patients, but this does not directly relate to the mechanism of resistance development.

Penicillin triggers the synthesis of resistant proteins

Rationale: Penicillin does not trigger the synthesis of resistant proteins. Resistance mechanisms, such as the production of beta-lactamase enzymes that break down penicillin, are typically encoded by genes that bacteria already possess or acquire through genetic exchange.

Conclusion:

The correct explanation for the increasing resistance of bacteria to penicillin is that previously resistant forms survived and reproduced better than non-resistant forms. This process is driven by natural selection, where the use of antibiotics creates an environment that favors the survival of resistant bacteria.