Practise Communicable (infectious) diseases. 12 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Communicable diseases are caused by pathogens. What is a pathogen?
A microorganism that causes an infectious disease.
What name is given to an organism, such as the midge, that carries a pathogen from one organism to another?
Vector
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy6 marks
Communicable diseases are caused by pathogens.
(a) What is a pathogen?[1]
(b) Which list contains only types of pathogen? Tick (✓) one box.[1]
Antibodies, bacteria, fungi and viruses
Bacteria, fungi, protists and viruses
Bacteria, enzymes, protists and viruses
Bacteria, fungi, platelets and viruses
(c) Give two ways that pathogens can be spread from one organism to another.[2]
(d) Bacteria that reproduce inside the body can make a person feel ill. How do bacteria make a person feel ill?[1]
(e) How do viruses cause damage in the body?[1]
Show the answer and mark scheme
(a)Answer: A microorganism that causes an infectious disease.
a microorganism that causes (infectious / communicable) disease
(b)Answer: Bacteria, fungi, protists and viruses
(c)Answer: Any two from: direct contact, water, air, food, vectors, body fluids.
(by) direct contact
(by / in) water
(through the) air / in droplets from coughs and sneezes
(in) food
(by) vectors / animals such as insects
(through) body fluids / blood / sexual contact
(d)Answer: They produce toxins (poisons) that damage tissues.
(they) produce toxins / poisons (that damage tissues)
(e)Answer: They reproduce inside cells, which damages the cells.
(they) live and reproduce inside cells, damaging the cells
Question 2Medium6 marks
A stomach infection spread rapidly among 2400 passengers on a cruise ship. The pathogen is present in vomit and faeces, spreads by touching contaminated surfaces, and can survive outside the body for several days.
(a) Suggest two reasons why the infection spread so quickly among the passengers.[2]
(b) 312 of the 2400 passengers had symptoms. Calculate the percentage of passengers who had symptoms.[2]
(c) The crew closed the buffet and asked passengers to use alcohol hand gel before eating. Suggest two reasons why hand gel alone may not fully control the outbreak.[2]
Show the answer and mark scheme
(a)
many people live close together in a confined space, so there is a lot of close contact
many people touch the same surfaces, e.g. handrails and buffet equipment
the pathogen survives for several days outside the body, so surfaces stay contaminated
(b)Answer: 13%
312 ÷ 2400 × 100
13 (%)
(c)
hand gel cleans only hands, not contaminated surfaces or objects
passengers can pick up the pathogen again by touching contaminated surfaces after using the gel
infected passengers are still mixing with other passengers / are not isolated
the pathogen is also spread in vomit, not only on hands
some passengers may not use the gel, or may not use it properly / the gel may not kill this pathogen
Question 3Hard8 marks
Bluetongue is a disease of sheep and cattle. It is caused by a virus. The virus is carried from one animal to another by small biting insects called midges. It is not usually spread by direct contact between animals. Midges breed in wet mud and animal dung. They are most active around dusk and dawn.
(a) What name is given to an organism, such as the midge, that carries a pathogen from one organism to another?[1]
(b) Farmers are given this advice to reduce the spread of bluetongue:
keep animals indoors from dusk until dawn
treat animals with an insecticide
move animals away from wet, muddy fields.
Explain how each piece of advice reduces the spread of bluetongue.[3]
(c) A farmer moved infected sheep into a separate field, away from the healthy sheep. The disease still spread to the healthy sheep. Suggest why moving the infected sheep did not stop the spread.[2]
(d) Vaccines against bluetongue are available. Explain why vaccinating most of the sheep on a farm also helps to protect the sheep that have not been vaccinated.[2]
Show the answer and mark scheme
(a)Answer: Vector
vector
(b)
(indoors) animals are bitten less often when the midges are most active
insecticide kills the midges / vectors (so fewer animals are bitten)
fewer midges breed / live near the animals (away from wet mud)
(c)
midges can fly from one field to another
(so) a midge can pick up the virus from an infected sheep and pass it to a healthy sheep
(d)
vaccinated sheep do not become infected / do not carry the virus
(so) fewer midges pick up the virus, so an unvaccinated sheep is less likely to be bitten by an infected midge