A gardener notices that some tomato plants have yellow, mottled leaves. Some of the plants also have large swellings on their stems, near the soil.
Describe how the disease could be diagnosed in the field.
The swellings are caused by crown gall disease.
Name the type of pathogen that causes crown gall disease.
In a laboratory, scientists can identify a plant pathogen by testing a sample for the DNA of the pathogen or for its antigens.
Explain why these tests can identify the exact pathogen when looking at the symptoms may not.
Suggest why identifying the pathogen quickly helps to control the spread of the disease.
181 exam-style questions on OCR GCSE Biology 6.3 Monitoring and maintaining health, covering 6.3.1 Health and disease, 6.3.2 Interactions between diseases, 6.3.3 Spread of communicable diseases, 6.3.4 Common infections and diseases, 6.3.5 Physical plant defence responses, 6.3.6 Chemical plant defence responses, 6.3.7 Detecting and identifying plant diseases, 6.3.8 White blood cells and platelets, 6.3.9 Non-specific defence systems, 6.3.10 The immune system, 6.3.11 Monoclonal antibodies, 6.3.12 Vaccines and medicines, 6.3.13 Aseptic techniques, 6.3.14 Discovery and development of new medicines, 6.3.15 Causes of non-communicable diseases, 6.3.16 Treatments for cardiovascular disease, 6.3.17 Lifestyle factors and non-communicable diseases, 6.3.18 Cancer, 6.3.19 Stem cells in medicine, 6.3.20 Gene technology in medicine, and 6.3.21 The human genome and medicine. Each one has a worked solution and a mark scheme showing where the marks go.