Let me share with you a comparison between cyanobacteria and algae.
| Aspect | Cyanobacteria | Algae |
| Classification | Prokaryotic cells with no membrane-bound nucleus or organelles | Eukaryotic cells with a membrane-bound nucleus and organelles |
| Pigments | · Chlorophyll a (primary pigment) · Phycocyanin · Other accessory pigments | · Chlorophyll a · Chlorophyll b · Carotenoids · xanthophylls |
| Cell wall composition | Peptidoglycan | Cellulose |
| Types of reproduction | · Binary fission · Fragmentation · Hormogonia formation | · Binary fission · Fragmentation · Spore formation · Sexual reproduction |
| Habitat | · Freshwater · Marine environments · Terrestrial habitats | · Freshwater · Marine environments · Damp terrestrial environments |
| Role in nitrogen fixation | Fix atmospheric nitrogen into a usable form | Algae do not fix atmospheric nitrogen |
| Ecological Role | Some bacteria form symbiotic relationships with plants e.g., lichens | Provide oxygen and serve as the base of the food chain |
| Cellular Organization | Unicellular or multicellular with simple structures | Multicellular |
| Motility | · Gliding movement · Oscillatory movement, often facilitated by gas vesicles | · Some are non-motile · Others may have flagella or other structures for movement |
| Uses | · Used as food supplements e.g., Spirulina · Bioremediation · In agriculture for nitrogen fixation | · Used in various industries, including food production e.g., seaweed · Biofuel production · As indicators of water quality |
| Examples
| · Anabaena · Spirulina · Nostoc
| · Chlamydomonas · Diatoms · Spirogyra · Ulva |