Mint and witch hazel are used to make mild antiseptics. Scientists are investigating the chemicals in these plants as possible new antibiotics.
Explain why mint and witch hazel plants make these chemicals.
A scientist tested an extract of mint against two species of bacteria. The extract killed species 1 but not species 2. Suggest what this shows about the antibacterial chemical in mint.
Give one reason why a chemical from a plant cannot be used as a medicine as soon as it is discovered.
58 exam-style questions on AQA GCSE Biology 3.3 Plant disease, covering 3.3.1 Detection and identification of plant diseases and 3.3.2 Plant defence responses. Each one has a worked solution and a mark scheme showing where the marks go.