Basic microbiology techniques — A/L Biology

How do I practise Basic microbiology techniques?

1 question with a worked solution

1. In standard autoclave sterilization of nutrient agar media, what temperature, pressure, and time duration are officially recommended?
   1. A) 121 °C, 15 psi (103 kPa), 15-20 minutes
   2. B) 160 °C, atmospheric pressure, 2 hours
   3. C) 100 °C, atmospheric pressure, 30 minutes
   4. D) 134 °C, 30 psi, 5 minutes
   Check my answer

   Correct answer: A) 121 °C, 15 psi (103 kPa), 15-20 minutes

   Autoclaving uses moist heat under pressure at 121 °C and 15 pounds per square inch (psi) gauge pressure for 15-20 minutes to reliably destroy bacterial endospores.

   Show worked solution

   Step 1: Identify moist heat sterilization standards for culture media. Step 2: 121 °C (250 °F) at 15 psi achieves destruction of highly heat-resistant endospores (e.g., Geobacillus stearothermophilus). Step 3: Standard exposure duration is 15-20 minutes. Answer: 121 °C, 15 psi (103 kPa), 15-20 minutes.
   Modelled on: the A/L Biology examination pattern

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Where does Basic microbiology techniques fit in the syllabus?

Year 1 · Term 3