Other Kingdoms
Biology: Edexcel IGCSE, topic 1.2.5
Fungi, Protoctists and Bacteria
Fungi and protoctists are eukaryotic organisms, but bacteria are prokaryotes.
Fungi
- Fungi cells have cell walls (that contain a substance called chitin) and no chloroplasts.
- Fungi can be multicellular or unicellular and they are saprotrophic (they feed by secreting digestive enzymes and absorbing broken down decaying matter), and often store carbohydrates as glycogen.
- Their bodies are made up of mycelium, which contains many thread-like structures called hyphae.
- Mushrooms and single-celled yeast are examples.
Bacteria
- Bacteria are unicellular and they have cell walls and circular loops of DNA (which is not inside a nucleus).
- Some bacteria photosynthesise, and some feed off decaying matter.
- Bacteria can be rod-shaped (like Lactobacillus which turns milk into yoghurt)or spherical (like Pneumococcus which causes pneumonia).
Protoctists
- Protoctists are unicellular, and their cells have nuclei (membrane-bound structures that contain the cell's genetic materials).
- Some, like Amoeba, are similar to animal cells. Some, like Chlorella, are like plant cells and have chloroplasts.
Test yourself on Other Kingdoms
Which option is true with reference to prokaryotes and protoctists?
Which of these is not a shape that bacteria can be?