Exam questions · Biology · Communicable Diseases
Pathogens and the Spread of Disease
- 7 exam questions
- 17 marks
- 8 quick checks
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1 State [1 mark]
Name two types of pathogen.
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Model answer
Any two of: viruses, bacteria, protists, fungi.
Mark scheme
- Two types named — 1 mark
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2 Describe [2 marks]
Describe two ways in which pathogens can be spread.
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Model answer
By direct contact, for example touching an infected person. By air, for example in droplets from a cough or sneeze. By water, for example in contaminated drinking water.
Mark scheme
- A first way — 1 mark
- A second way — 1 mark
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3 Explain [2 marks]
Explain how bacteria can make a person feel ill.
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Model answer
Bacteria reproduce rapidly inside the body. They may produce toxins (poisons) that damage tissues and make us feel ill.
Mark scheme
- Reproduce rapidly — 1 mark
- Produce toxins that damage tissues — 1 mark
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4 Explain [2 marks]
Explain why viruses are harmful to the cells they infect.
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Model answer
Viruses live and reproduce inside cells. This causes cell damage.
Mark scheme
- Live and reproduce inside cells — 1 mark
- Damage the cells — 1 mark
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5 Suggest [3 marks]
A student has a cold. Suggest three ways the student could reduce the spread of the cold to others.
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Model answer
Cover the mouth and nose when coughing or sneezing, use tissues and put them in the bin. Wash hands often. Stay away from other people while infectious.
Mark scheme
- Cover mouth when sneezing — 1 mark
- Wash hands — 1 mark
- Stay away from others / isolate — 1 mark
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6 Explain [3 marks]
Malaria is spread by mosquitoes. Explain how destroying the breeding sites of mosquitoes reduces the spread of malaria.
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Model answer
Mosquitoes are the vector that carries the pathogen from one person to another. Mosquitoes breed in standing water. If the breeding sites are destroyed there are fewer mosquitoes, so fewer people are bitten and infected.
Mark scheme
- Mosquito is the vector — 1 mark
- Fewer mosquitoes — 1 mark
- Fewer people infected — 1 mark
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7 Explain [4 marks]
Explain why a disease caused by a pathogen spreads more quickly in a crowded town than in a village in the countryside.
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Model answer
In a crowded town there are more people close together, so there is more direct contact between them. Pathogens that spread by air are breathed in by more people, and pathogens in water or on surfaces can be passed on more easily. Fewer people can isolate themselves, so more people are exposed.
Mark scheme
- More people in close contact — 1 mark
- Spread by air or droplets more easily — 1 mark
- Spread by surfaces and water — 1 mark
- Harder to isolate infected people — 1 mark
Quick check
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1
Which of these is a pathogen?
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C: A virus
A virus can cause infectious disease, so it is a pathogen.
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2
What are toxins?
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A: Poisons made by bacteria
Toxins are poisons made by bacteria that damage tissues.
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3
Where do viruses reproduce?
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D: Inside living cells
Viruses can only reproduce inside the cells of a host.
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4
Which way of spreading disease does a sneeze involve?
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B: By air
A sneeze sends droplets containing pathogens into the air.
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5
What is a vector?
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C: An organism that carries a pathogen
A vector carries a pathogen from one host to another.
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6
Which of these helps to stop the spread of disease?
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A: Washing hands
Washing hands removes pathogens, so it stops them being passed on.
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7
Which pathogen is a single-celled eukaryote?
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D: A protist
Protists are single-celled eukaryotes, and some of them cause disease.
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8
Why is vaccination a good way of controlling a disease?
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B: It makes people immune
Vaccinated people are immune, so they do not catch or pass on the disease.