Fungal and protist diseases (AQA GCSE Biology): Revision Notes
Fungal and protist diseases
What are fungi and protists?
Both fungi and protists are organisms that have a nucleus (called eukaryotic organisms). Some of these can cause diseases in humans, animals, and plants.
Fungi
Fungi are organisms that can be single-celled or multi-celled. They have some key features:
- Cell walls - like plants, but made of different materials
- No chloroplasts - they can't make their own food through photosynthesis
- Examples include yeasts and moulds
Some fungi can be harmful because they produce toxins - poisonous substances that make living things ill.
Useful fact: Yeasts are single-celled fungi that we use to make bread and alcoholic drinks.
Protists
Protists are quite different from fungi:
- They are single-celled organisms only
- They don't form tissues like animals and plants do
- There are many different types of protists
- Some protists are parasites - they live inside other organisms and cause harm
Malaria - a serious protist disease
What causes malaria
Malaria is caused by protist parasites. These tiny organisms get into your blood and liver cells.
How malaria spreads
The disease spreads through a life cycle involving mosquitoes:
How Malaria Spreads: The Complete Life Cycle
- An infected mosquito bites a person and injects the malaria parasites
- The parasites multiply in the person's liver
- They then infect red blood cells
- When a mosquito bites this infected person, it picks up the parasites
- The cycle continues when this mosquito bites another person
The mosquito acts as a vector - it carries the disease from one person to another.
Symptoms and effects
- Recurring fever - comes and goes in episodes
- Can cause death if not treated properly
Prevention methods
Effective Prevention Strategies:
- Remove standing water where mosquitoes breed (like ditches and ponds)
- Use mosquito nets at night to avoid being bitten
- Spray insecticides to kill mosquitoes
Rose black spot - a plant fungal disease
This fungal disease affects roses and other plants:
What it does
- Causes purple or black spots on leaves
- Spots often turn yellow and drop off
- Reduces photosynthesis because there are fewer healthy leaves
- Plants can't make enough food for healthy growth
How it spreads
- Fungal spores travel in the wind
- Spores can also spread through water in rain splashes
Treatment
Treatment Options:
- Spray fungicides on the plants - these are chemicals that kill fungi
- Remove and destroy infected leaves to stop the disease spreading
Ringworm - a human fungal disease
Despite its name, ringworm isn't caused by worms - it's a fungal infection.
How it spreads
- Direct contact with infected skin
- Contaminated clothes or towels
- Contact with infected animals
Prevention
Prevention Methods:
- Wash hands regularly, especially after touching animals
- Don't share towels, clothes, or personal items
- Keep skin clean and dry
Remember!
Key Points to Remember:
- Fungi and protists are organisms with a nucleus that can cause diseases
- Malaria is spread by mosquitoes and affects blood cells - prevent with nets and removing standing water
- Rose black spot reduces photosynthesis in plants - treat with fungicides
- Fungal diseases like ringworm spread through contact - prevent with good hygiene
- Vectors like mosquitoes carry diseases from one organism to another