1. What are pathogens, and what types of organisms can be considered pathogens ?
Answer
Pathogens are microorganisms that cause infectious disease. Viruses, bacteria, protists or fungi can be considered pathogens.
2. What type of pathogen causes malaria ?
Answer
Malaria is caused by protists, which are eukaryotic microorganisms.
3. What is a "placebo" ?
Answer
Something that looks like the real drug, but contains no drug.
4. Describe how bacteria can make us feel ill.
Answer
Bacteria can reproduce rapidly inside our body and may produce poisons (toxins) that damage tissues and make us feel ill.
5. How can the spread of gonorrhoea be controlled ?
Answer
It can be treated with antibiotics or prevented by using a barrier method of contraception, such as a condom.
6. HIV is a virus. How is it transmitted, and what are the initial symptoms of infection ?
Answer
HIV is spread through sexual contact or the exchange of body fluids, such as blood when drug users share needles. It initially causes a flu-like illness.
7. Explain how a vaccine works to prevent disease.
Answer
A small amount of dead or weakened virus is injected into the body. White blood cells (lymphocytes) then produce antibodies specific to that virus. If the same virus enters the body again, the white blood cells rapidly produce large quantities of antibodies to destroy it and prevent disease.
8. What are the symptoms of rose black spot and how does it affect plant growth ?
Answer
Purple or black spots develop on the leaves, which often turn yellow and fall off early. As a result, the plant cannot synthesise the proteins needed for growth.
9. Digitalis is a heart drug. Name the groups of drugs that aspirin and penicillin belong to.
Answer
Aspirin is a painkiller. Penicillin is an antibiotic.
10. At the start of clinical trials, phase 1 uses small numbers of healthy volunteers. Give the reason why very low doses of drug are given at the start of this phase ?
Answer
To check for side effects or unexpected reactions to the drug.