Community Q&A
A-Level Biology May/June 2024 Q1(c): The vector for Zika virus is the mosquito Aedes aegypti. The mosquito feeds on the bloo…
A-Level Biology · Paper 9700/23 · May/June 2024 · Question 1(c) · [3 marks]
The vector for Zika virus is the mosquito Aedes aegypti. The mosquito feeds on the blood of an infected person and transmits the virus to another person when it feeds again. Describe the similarities and differences between the transmission of Zika virus disease and the transmission of malaria.
A full-marks model answer with a mark-by-mark examiner breakdown is below.
1 answer
- accepted ✓
Similarities
- Both Zika and malaria are transmitted by vectors. Specifically, both diseases are transmitted by mosquitoes. (2)
- In both cases, the mosquito vector feeds on the blood of an infected individual to pick up the pathogen and then transmits it to an uninfected person during a subsequent blood meal. Therefore, both are considered blood-borne diseases. (1)
Differences
- The genus of the mosquito vector is different for each disease. Zika is transmitted by the Aedes mosquito, whereas malaria is transmitted by the Anopheles mosquito. (1)
How the marks are awarded
- B1 — Stating that both diseases are transmitted by vectors, and more specifically by mosquitoes.
- B1 — Identifying that both are blood-borne diseases, as the vector acquires the pathogen by feeding on blood.
- B1 — Correctly stating the difference in the mosquito vector: Aedes for Zika and Anopheles for malaria.
Common mistakes
- Confusing the pathogen with the vector, for example, stating that malaria is transmitted by 'Plasmodium' instead of the Anopheles mosquito.
- Being too vague, such as saying 'insects' transmit the diseases instead of the more precise term 'mosquitoes' which is required by the mark scheme.
- Only providing similarities or only providing differences, thereby failing to answer the full scope of the question which asks for both.
- Incorrectly naming or spelling the mosquito genera, for instance, mixing up Aedes and Anopheles.
Examiner tip: For 'compare and contrast' questions, structure your answer with clear headings for 'Similarities' and 'Differences' to ensure you address both parts of the prompt and make it easy for the examiner to award marks.
AI-generated model answer, grounded in the official Cambridge mark scheme and reviewed by the MarkScheme team. Mark your own answer to this question →
Your answer
Sign in to answer this question.