AQA GCSE Biology Foundation (8461), Foundation tier · Infection and response › Communicable diseases
Practise Protist diseases. 6 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
Malaria is the protist disease in the specification. You need to know that it is caused by a protist, that mosquitoes are the vector, its main symptom, and how its spread is controlled by targeting mosquitoes.
Key facts
Malaria is caused by a protist
Vector = mosquito (carries the protist from person to person)
Symptom: recurrent episodes of fever; can be fatal
The pathogens that cause malaria are protists (single-celled organisms).
Malaria causes recurrent episodes of fever: the fever goes away and then comes back again and again.
Malaria can be fatal.
The mosquito vector
diagram
The malarial protist has a life cycle that includes the mosquito.
A mosquito that bites an infected person takes in the protist with the blood. When it later bites another person, it passes the protist into that person's blood.
The mosquito is a vector: it carries the pathogen from one person to another.
The mosquito carries the protist from one person to the next.
Malaria is not spread by touching an infected person or through the air.
Controlling the spread
Prevent mosquitoes breeding: mosquitoes lay their eggs in still water, so drain or treat areas of standing water, e.g. ponds and old containers.
Kill adult mosquitoes with insecticides, e.g. sprayed inside homes.
Use mosquito nets over beds (often treated with insecticide) to avoid being bitten at night.
Each method means fewer mosquitoes or fewer bites, so the protist is passed to fewer people.
How to answer each type of question
Recall: pathogen, vector and symptom
1 mark eachGrade 3
Pathogen = protist; vector = mosquito.
For the symptom, say that the fever is recurrent.
Example. (a) What type of pathogen causes malaria? (b) Name the animal that spreads malaria. (c) Give the main symptom of malaria.
Show the model answerHide the model answer
(a) A protist (1) (b) Mosquito (1) (c) Recurrent episodes of fever (1)
Don’t lose marks
Saying malaria is caused by the mosquito, or by a virus or a bacterium. It is caused by a protist; the mosquito carries it.
Saying malaria spreads directly from person to person, e.g. by coughing or touching.
Writing 'kill the mosquitoes' without explaining why it helps: fewer mosquitoes means fewer bites, so fewer people are infected.
Writing just 'fever' when the question wants the pattern: the fever is recurrent (it keeps coming back).
More tips
Memory tricks
Malaria = P and M: a Protist carried by a Mosquito.
Break the chain: fewer mosquitoes (stop them breeding) or fewer bites (nets) = fewer infections.
The mosquito is the vector; the protist is the pathogen. Don't swap them.
Exam technique
Always name the vector and say what it does: it carries the protist from an infected person to another person.
Explanation marks come from the chain: method → fewer mosquitoes or fewer bites → fewer people infected.
In data questions, quote numbers and use percentage change where the question asks you to compare.
What each grade needs
What you need to be able to do, from the first marks up to the top grade.
Grade 3
Name a disease caused by a protistMalaria is caused by a single-celled protist.
Grade 4
Describe the main symptom of malariaRecurrent episodes of fever (the fever keeps coming back); malaria can be fatal.
Grade 4
Identify the vector of malariaMosquitoes carry the protist and pass it to people when they bite them.
Grade 5
Describe how the spread of malaria is controlledStop mosquitoes breeding, and use mosquito nets to avoid being bitten.
Quick recall
Cover the answers and test yourself. The app has these as flashcards that come back just before you'd forget them.
Malaria is spread by mosquitoes. What name is given to an animal that spreads a pathogen?
Vector
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy5 marks
Malaria is a disease that affects millions of people every year.
(a) What type of pathogen causes malaria? Tick (✓) one box.[1]
Bacterium
Fungus
Protist
Virus
(b) Malaria is spread by mosquitoes. What name is given to an animal that spreads a pathogen?[1]
(c) Give one symptom of malaria.[1]
(d) Give two ways that the spread of malaria can be controlled.[2]
Show the answer and mark scheme
(a)Answer: Protist
(b)Answer: Vector
vector
(c)Answer: Recurrent episodes of fever.
(recurrent episodes of) fever
(d)
stop mosquitoes breeding, e.g. drain standing water
sleep under mosquito nets
kill mosquitoes with insecticide
use insect repellent / cover the skin
Question 2Medium6 marks
The protist that causes malaria has a life cycle that includes the mosquito. When a mosquito bites an infected person, it takes in protists with the blood. The protists develop inside the mosquito and are passed to the next person the mosquito bites. Mosquitoes lay their eggs in still water. Most mosquitoes that spread malaria feed at night.
(a) Explain why sleeping under a mosquito net reduces the spread of malaria.[2]
(b) Explain how draining areas of still water reduces the spread of malaria.[2]
(c) Suggest two reasons why malaria is more common in hot, wet countries than in cold, dry countries.[2]
Show the answer and mark scheme
(a)
mosquitoes cannot bite the person (at night)
(so) protists are not passed to the person / mosquitoes cannot take in protists from an infected person
(b)
mosquitoes cannot lay eggs / breed
(so) there are fewer mosquitoes / vectors to carry the protists to people
(c)
more still water for mosquitoes to breed in
mosquitoes survive / breed / are active all year in warm conditions
the protists develop more quickly inside mosquitoes in warm conditions