1. Which system destroys pathogens that enter the body ?
Answer
The immune system destroys pathogens.
2. What is a "double blind trial" ?
Answer
A trial where neither the doctor nor the patient know if they are getting the real drug or a placebo.
3. Salmonella is a type of food poisoning caused by bacteria. What is the most common way it can be spread ?
Answer
By bacteria ingested in food that was prepared in unhygienic conditions.
4. Explain why it is important to use specific antibiotics to treat a bacterial infection.
Answer
Different antibiotics work in different ways, so specific antibiotics will kill specific bacteria.
5. Why antibiotics cannot be used to treat viral diseases ?
Answer
Antibiotics cannot kill viral pathogens. They are only effective against bacteria because viruses live inside cells.
6. Why is it an advantage if a large proportion of the population is vaccinated against measles ?
Answer
It can lead to herd immunity, which reduces the spread of infection.
7. Malaria is a disease caused by a protist. How is it transmitted, and what effects does it have on the body ?
Answer
Malaria can be transmitted through the bite of a mosquito. It causes fever (may be fatal), headache, nausea and abdominal pain.
8. Give the reasons why new drugs are tested extensively for toxicity, efficacy and dose.
Answer
New drugs are tested for toxicity to ensure they are not poisonous or harmful, for efficacy to confirm they effectively treat the disease, and for dosage to determine the optimum amount to administer.
9. Some clinical trials are double blind trials with one group getting the drug and one group getting a placebo. Why does one group get a placebo ?
Answer
For comparison with the group being given the drug, to see whether the drug works (rather than any improvement being due to the placebo effect).