Microbes and Disease
Year 8 ๐ซ Physiology & Health Bacteria, viruses, fungi; how pathogens cause disease.
๐ฆ Pathogens
Pathogens are microorganisms that cause disease. The four main types are bacteria, viruses, fungi, and protozoans.
| Pathogen | Example disease | Structure | Treatment |
|---|---|---|---|
| Bacteria | Tuberculosis, cholera, salmonella | Prokaryotic cell; no nucleus | Antibiotics |
| Virus | Influenza, HIV, COVID-19 | Protein coat + nucleic acid; not a cell | Antivirals (few); vaccines |
| Fungus | Athlete's foot, ringworm | Eukaryotic; has nucleus | Antifungals |
| Protozoan | Malaria (Plasmodium) | Eukaryotic single-celled organism | Antimalarials |
Antibiotics kill bacteria โ they do NOT work against viruses. Overuse of antibiotics leads to antibiotic resistance.
๐ก๏ธ Body Defences
- Skin โ physical barrier; sebum (acidic) kills bacteria
- Mucus and cilia โ in airways; trap pathogens; cilia sweep mucus away
- Stomach acid โ pH 2; kills most swallowed pathogens
- Phagocytes โ white blood cells; engulf and digest pathogens (phagocytosis)
- Lymphocytes โ produce antibodies specific to each antigen; form memory cells
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Interactive Demo โ Microbes and Disease
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