1. What type of pathogen causes salmonella (food poisoning) and gonorrhoea ?
Answer
Bacteria cause both of these diseases.
2. Name the scientist who discovered penicillin.
Answer
Penicillin was discovered by Alexander Fleming.
3. Explain how the white blood cells defend the body against pathogens.
Answer
White blood cells destroy pathogens by phagocytosis. This is when a white blood cell (phagocyte) engulfs a pathogen and then destroys it by digesting it. Other types of white blood cells (lymphocytes) produce chemicals called antibodies. Antibodies have specific shapes and only bind to and destroy specific pathogens. Lymphocytes also produce chemicals called antitoxins to counteract toxins (poisons) produced by some pathogens.
4. Suggest some ways of controlling the spread of salmonella.
Answer
By vaccinating poultry, washing hands thoroughly before and after handling food, cleaning kitchen surfaces before and after preparing food, avoiding eating undercooked eggs, beef, pork and especially poultry.
5. Describe how viruses can make us ill.
Answer
Viruses may reproduce rapidly inside the body. Viruses live and reproduce inside cells, causing cell damage.
6. Measles is a viral illness. What are the symptoms of measles, and how is it spread ?
Answer
The symptoms of measles are fever and a red skin rash. It is spread through inhalation of droplets from coughs and sneezes.
7. What are the symptoms of tobacco mosaic virus (TMV) and how does it affect plant growth ?
Answer
A distinctive pattern of discolouration on the leaves that looks like mosaic. Photosynthesis is reduced, so less glucose is produced and plant growth is reduced.
8. Explain some methods used to control the spread of malaria.
Answer
Mosquitoes spread malaria when they bite, so using mosquito nets over beds at night or wearing insect repellent prevents mosquitoes from biting. Draining ditches and pools of still water prevents mosquitoes from breeding.
9. Pre-clinical testing of a new drug happens in a laboratory. During this phase, what are the drugs tested on, and what is the primary goal of this testing ?
Answer
Pre-clinical testing involves the use of cells, tissues, or live animals. This stage ensures that the drug is both effective and safe.