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Two students designed an experiment to investigate antibiotic resistance in *Escherichia coli* bacteria - VCE - SSCE Biology - Question 11 - 2021 - Paper 1
Question 11
Two students designed an experiment to investigate antibiotic resistance in *Escherichia coli* bacteria. They began with an E. coli culture. The following procedure... show full transcript
Worked Solution & Example Answer:Two students designed an experiment to investigate antibiotic resistance in *Escherichia coli* bacteria - VCE - SSCE Biology - Question 11 - 2021 - Paper 1
Step 1
Identify any two controlled variables for this experiment.
Answer
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Volume of E. coli first applied to plates: Ensuring consistent amounts of the E. coli culture are used to avoid variations in bacterial growth due to differing initial quantities.
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Incubation temperature: Maintaining a constant temperature during incubation ensures that any changes in bacterial growth are due to the concentrations of ampicillin rather than variations in environmental conditions.
Step 2
Write a suitable hypothesis for this experiment.
Answer
The hypothesis is: If E. coli is exposed to low (1 µg/mL) concentrations of ampicillin, then there will be increased growth of E. coli as compared to higher concentrations of ampicillin, which will inhibit bacterial growth. This is based on the premise that lower levels of antibiotic allow for survival and proliferation, while higher levels result in decreased growth or death of E. coli.