1. Which body cells does HIV attack, and which group of drugs is used to control it ?
Answer
HIV attacks the body’s immune cells (or white blood cells). Antiretroviral drugs are used to control it.
2. Aspirin is a type of medicine called a painkiller. What is the purpose of a painkiller ?
Answer
A medicine that treats the symptoms of disease, but does not kill pathogens.
3. Describe how the skin and the ciliated epithelium in the trachea and bronchi defend against pathogens.
Answer
The outer layer of skin is made of dead cells that are difficult to penetrate. Glands secrete an oily substance called sebum that inhibits the growth of microorganisms.
Pathogens stick to mucus and then the cilia move the mucus away from the lungs towards the throat to be swallowed.
4. Give some symptoms of salmonella food poisoning.
Answer
Fever, abdominal cramps, vomiting and diarrhoea.
5. Why can gonorrhoea not be treated with penicillin anymore ?
Answer
Many strains of gonorrhoea bacteria have developed resistance to antibiotics.
6. Explain why it is difficult to develop drugs that kill viruses.
Answer
Viruses live and reproduce inside cells, so drugs that kill viruses may also damage body tissues.
7. The graph in the figure below shows the number of antibodies against the measles virus in a child’s blood after the first and second measles vaccine. Describe the differences in the production of antibodies after the second vaccination compared with after the first vaccination.
Answer
More antibodies are produced, and at a faster rate, after the second vaccination compared to the first. Additionally, antibody levels remain elevated for a longer period following the second dose.
8. Rose black spot is a plant disease. Describe some methods used to treat it.
Answer
Using fungicides (chemicals that kill the pathogen) and removing the affected leaves.
9. Describe the difference between the traditional source of drugs and the source of new drugs.
Answer
Traditionally drugs were extracted from plants and microorganisms, whereas most new drugs are synthesised by chemists in the pharmaceutical industry.