A student investigates one way in which the skin protects the body.
Two samples each contained 1200 bacteria of a type that can cause disease. Sterile water was added to one sample. A secretion made by the skin was added to the other sample.
The table shows the results.
| Liquid added | Number of living bacteria after 30 minutes |
|---|---|
| Sterile water | 1160 |
| Skin secretion | 290 |
Give the term used for a microorganism that causes disease.
Explain how the results support the idea that the skin secretion helps to protect the body.
The skin secretion is part of a non-specific defence.
Give one reason why this defence is described as non-specific.
252 exam-style questions on AQA GCSE Biology 3.1 Communicable diseases, covering 3.1.1 Communicable (infectious) diseases, 3.1.2 Viral diseases, 3.1.3 Bacterial diseases, 3.1.4 Fungal diseases, 3.1.5 Protist diseases, 3.1.6 Human defence systems, 3.1.7 Vaccination, 3.1.8 Antibiotics and painkillers, and 3.1.9 Discovery and development of drugs. Each one has a worked solution and a mark scheme showing where the marks go.