Fungal and Protist Diseases

This lesson explores fungal diseases and further detail on protist diseases as required by the AQA GCSE Combined Science Trilogy specification (8464). The main examples are rose black spot (fungal) and malaria (protist). You also need to understand how these pathogens differ from bacteria and viruses.

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Fungal Pathogens — An Overview

Fungi are eukaryotic organisms that can be single-celled (e.g. yeast) or multicellular (e.g. mushrooms, moulds). Pathogenic fungi cause disease in plants and animals by:

1. Growing hyphae (thread-like structures) into the host's tissues
2. Releasing enzymes that digest and absorb nutrients from the host
3. Producing spores that spread to new hosts via wind, water, or contact

Feature	Detail
Cell type	Eukaryotic
Cell wall	Made of chitin (not cellulose)
Reproduction	Sexual and asexual; often by producing spores
How they feed	Secrete enzymes externally to digest organic matter, then absorb the nutrients (saprophytic or parasitic)

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Rose Black Spot