Biology 11–12 · Year 12
Antimicrobial action of antibiotics, antiseptics and tea tree oil by disc diffusion
Module 7: Infectious Disease (Prevention, Treatment and Control)
Teacher-led demonstration
A teacher carries out this activity as a demonstration. Its materials, steps, variables, misconceptions and sources are not published on the open web, and neither is any result, control or note that states a number or an amount: tutors and administrators read them on the learning platform, with the safety card first. The idea, the hazards and the curriculum references are below.
Open the procedure on the learning platform (tutor or administrator sign-in)
School laboratory, not for home
In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
The idea
A substance that stops bacterial growth leaves a clear zone around the disc it soaks, and the zone's width compares treatments, including a plant extract used in Aboriginal medicine.
Safety card
Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
Hazards
- Bacterial cultures (treated as potentially pathogenic)
- Ethanol or essential oil near a flame
- Antibiotic discs: sensitisation
Controls
- Safe strains only from a recognised supplier; aseptic technique; plates taped and never opened by learners; disposal by autoclave
- Keep alcohol and oils away from the flame
- Forceps only; wash hands; anyone with a known antibiotic allergy avoids the discs
- Anyone who is unwell or taking immunosuppressive medication does not handle cultures, as the source advises
Note
It states a number or an amount, which may be part of the method, so it is shown with the method to tutors and administrators on the learning platform.
What you should see
It states a number or an amount, which may be part of the method, so it is shown with the method to tutors and administrators on the learning platform.
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.
- Biology Stage 6 Syllabus (2017), current: Year 11 taught to the end of 2026 and Year 12 to Term 3 2027BIO12-14BIO11/12-2BIO11/12-3BIO11/12-4
- Biology 11–12 Syllabus (2025), Year 12 focus area Diseases; new syllabus not yet taught: Year 11 from Term 1 2027, Year 12 from Term 4 2027BI-12-02
- Biology 11–12 Syllabus (2025), Year 12 Working scientifically; new syllabus not yet taught: Year 11 from Term 1 2027, Year 12 from Term 4 2027BI-12WS-02BI-12WS-03BI-12WS-04
- Australian Curriculum v9No Australian Curriculum v9 code is listed.