A researcher studying bacterial bioluminescence (*Vibrio fischeri*) sets up four separate culture tubes to evaluate light output under various conditions. Match each experimental setup (left) with its corresponding role or baseline condition in the study (right).
- Culture tube containing *V. fischeri* in standard nutrient broth with no test additives.Baseline control used to measure standard bacterial light production under normal growth conditions.
- Culture tube containing standard nutrient broth only, without *V. fischeri* bacteria.Negative control used to verify that the nutrient broth itself generates no background luminescence.
- Culture tube containing *V. fischeri* in nutrient broth mixed with a known chemical inhibitor of bioluminescence.Positive control used to confirm that light suppression can be successfully detected by the apparatus.
- Culture tube containing *V. fischeri* in nutrient broth mixed with an uncharacterized synthetic compound.Experimental treatment group manipulated to test the unknown effect of the new compound.
Cevap
The correct pairings match each setup to its specific function: the untreated culture provides the baseline control, the broth-only tube serves as the negative control, the culture with a known inhibitor acts as the positive control, and the culture with the synthetic compound represents the experimental group.
Each setup directly corresponds to its purpose: the untreated bacterial culture measures standard baseline output; the medium-only tube serves as a negative control to rule out background light from broth; the tube with a known inhibitor serves as a positive control demonstrating measurable light reduction; and the tube with the new compound is the experimental treatment evaluating an untested variable.
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Determining Control Groups and Baseline Conditions
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