Sample exam questions - infection and response - AQAThree- and four-mark questions

Four from the following:

1. They can often survive outside a host for long periods of time [1].
2. They then infect a suitable host cell [1].
3. They replicate themselves thousands of times [1].
4. They copy their genetic material (DNA or RNA) and protein coats [1].
5. This often causes the host cell to burst [1].
6. Other cells can then be infected [1].

Four marks from the following:

1. Through the air [1] like the common cold virus [1].
2. Through the dirty water [1] like cholera bacteria [1].
3. Through physical contact [1] like chlamydia bacteria [1].
4. Through contaminated food [1] like Escherichia coli bacteria [1].
5. By another animal [1] like badgers which some believe carry tuberculosis [1].

Four from the following:

1. Phagocytes surround any pathogens in your blood and engulf them [1].
2. Enzymes inside the phagocytes then breakdown the pathogen [1].
3. Lymphocytes recognise proteins on the surface of pathogens called antigens [1].
4. They then produce antibodies which make pathogens stick together [1].
5. Lymphocytes also produce antitoxins to neutralise the effects of toxins produced by pathogens [1].

Four from the following:

1. Risk factors are things that increase a person’s chance of developing a disease [1].
2. They can be part of a person’s lifestyle [1].
3. They can be substances in a person’s body or their environment [1].
4. Smoking is a risk factor for lung cancer [1].
5. Tar in cigarettes is a carcinogen [1].