# Malaria is a communicable disease caused by a protist spread through the bite of a female mosquito. Describe how the human body responds to the Plasmodium protist after it has entered the bloodstream, including the roles of phagocytes and lymphocytes.

> WJEC A-Level Biology (Wales) — 3.2 Respiration · Describe · 5 marks

> Malaria is caused by the protist Plasmodium falciparum, which is transmitted to humans via the bite of a female mosquito. Once inside the body, the protist enters the bloodstream where the immune system responds to destroy it.

## Mark scheme (5 marks)

1. White blood cells detect the protist using receptors on their cell surface that identify antigens on the surface of the pathogen
2. Phagocytes engulf / ingest the protist into the cell and digest it using enzymes (phagocytosis)
3. Lymphocytes release / trigger the release of antibodies that are specific / complementary to the antigens on the protist
4. Antibodies bind to the antigens on the protist to neutralise it / clump the cells together (agglutination) making it easier for the immune system to destroy it
5. Memory cells remain after the infection so that if the same pathogen enters the body again, it can be destroyed more quickly

## Key terms

- [phagocyte](https://www.gradenine.co.uk/glossary/phagocyte)
- [lymphocyte](https://www.gradenine.co.uk/glossary/lymphocyte)

## Related

- [Revision notes for WJEC A-Level Biology (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/malaria-is-a-communicable-disease-caused-44b06934) · Published by Druglandscape Ltd.