Yes, cyanobacteria are fundamentally involved in photosynthesis, both performing it themselves and historically playing a crucial role related to photosynthesis in other organisms.
Cyanobacteria: Masters of Photosynthesis
Cyanobacteria, often called blue-green algae (though they are bacteria, not algae), are ancient and incredibly important organisms. They are among the first life forms on Earth to develop the ability to photosynthesize, a process that changed the planet's atmosphere by producing oxygen.
As stated in the reference (Singh, 2018), cyanobacteria contain photosynthetic apparatus. This internal machinery allows them to capture light energy and convert carbon dioxide and water into glucose (sugar) and oxygen. This is the same fundamental process that powers most plant life and algae.
Unlike plants and algae, which house their photosynthetic machinery within specialized organelles called chloroplasts, in cyanobacteria, the chloroplast is absent (Singh, 2018). Instead, their photosynthetic components, such as chlorophyll and other pigments, are located within the cytoplasm, often arranged on internal membrane structures called thylakoids.
Key Aspects of Cyanobacteria and Photosynthesis:
- They perform photosynthesis: Cyanobacteria utilize their own photosynthetic apparatus to convert light energy into chemical energy.
- Oxygen production: Like plants, cyanobacteria release oxygen as a byproduct of photosynthesis.
- Absence of chloroplasts: While performing photosynthesis, they do not contain chloroplasts; the process occurs directly within their cell structure (Singh, 2018).
- Role in other organisms: The reference notes they "help them [cyanobacteria] to perform photosynthesis in higher plants and algae" (Singh, 2018). This points to the widely accepted theory that chloroplasts in plants and algae originally evolved from ancient cyanobacteria through a process called endosymbiosis. In this sense, cyanobacteria helped photosynthesis evolve and occur in these later organisms by becoming the photosynthetic organelles.
Whether found as unicellular or filamentous forms (Singh, 2018), cyanobacteria remain vital photosynthesizers in various aquatic and terrestrial environments. Their ability to perform photosynthesis makes them primary producers, forming the base of many food webs.
In summary, cyanobacteria actively perform photosynthesis themselves using their unique internal structure, and their evolutionary history is intrinsically linked to the very existence of photosynthesis in plants and algae.
