A scientist studied the effect of several new drugs (antibiotics x, y and z) to kill anthrax bacteria growing on petri plates with proper nutrients. the treatments in this study, applied to the bacterial media to compare with the currently used antibiotic are as follows: antibiotic x antibiotic y antibiotic z water currently used antibiotic which treatments are considered as negative and positive controls?
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In the experiment described, the scientist is attempting to compare the effectiveness of new antibiotics (X, Y, and Z) against anthrax bacteria with that of a currently used antibiotic. To do this, they use controls:
- Negative control: This should be a condition in which no response is expected. For this experiment, water is used as the negative control. Water is not an antibiotic, and thus it is not expected to kill the anthrax bacteria. Any change in the bacterial growth when treated with water is likely due to random fluctuations or other variables, not due to any antibacterial effect.
- Positive control: This should be a condition known to produce a response, thereby validating the experiment's setup. In this case, the currently used antibiotic serves as the positive control. Because this antibiotic is already known to be effective against anthrax bacteria, it shows that the experiment is functioning properly and that the bacteria are susceptible to antibiotics.
When analyzing the results, the effectiveness of new antibiotics X, Y, and Z can be compared to the results seen with the negative control (water) to ensure they demonstrate antibacterial properties, and to the positive control (currently used antibiotic) to see if they are as effective or perhaps even more effective at killing anthrax bacteria.