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Draw a flowchart showing the steps you could take to model Pasteur’s experiment to identify the role of microbes in decay - HSC - SSCE Biology - Question 24 - 2013 - Paper 1
Question 24
Draw a flowchart showing the steps you could take to model Pasteur’s experiment to identify the role of microbes in decay. Explain the importance of using controls ... show full transcript
Worked Solution & Example Answer:Draw a flowchart showing the steps you could take to model Pasteur’s experiment to identify the role of microbes in decay - HSC - SSCE Biology - Question 24 - 2013 - Paper 1
Step 1
Draw a flowchart showing the steps you could take to model Pasteur’s experiment to identify the role of microbes in decay.
Answer
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Take two identical swan-necked flasks.
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Partially fill each flask with broth for growing microorganisms.
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Boil both to sterilise them.
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Break the neck of one flask while leaving the neck intact on the other.
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Leave both flasks on a bench for 1 week.
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Observe the flasks for microbial growth.
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Make conclusions from the observations.
Step 2
Explain the importance of using controls in microbial experiments.
Answer
Controls in microbial experiments allow us to validate the results. The control ensures that the microbial growth is a result of experimental conditions rather than contamination.
For instance, when testing for the presence of microbes in food, the control agar plate is left unopened/unexposed. If no growth occurs in the control, it can indicate that the tested conditions are effective and not introducing unintended variables.