**Photosynthetic Pigments in Cyanobacteria**

Cyanobacteria, also known as blue-green algae, are a group of photosynthetic bacteria capable of performing oxygenic photosynthesis. They are ancient organisms that played a crucial role in shaping the Earth's atmosphere by producing oxygen billions of years ago.

Photosynthetic pigments are essential components of the photosynthetic machinery in cyanobacteria. These pigments absorb light energy and transfer it to the reaction centers, where the actual process of photosynthesis takes place. The major photosynthetic pigments found in cyanobacteria are chlorophyll a, phycocyanin, and phycoerythrin.

**1) Chromatophore**

Chromatophores are specialized membrane structures found in certain photosynthetic bacteria, such as purple bacteria and green sulfur bacteria. However, cyanobacteria do not possess chromatophores. Therefore, the photosynthetic pigments in cyanobacteria are not found in chromatophores.

**2) Chloroplast**

Chloroplasts are the organelles responsible for photosynthesis in higher plants and algae. They contain chlorophyll and other pigments, which are organized into various membrane structures called thylakoids. However, cyanobacteria do not have chloroplasts like higher plants. Instead, they have a primitive form of photosynthetic machinery that is not enclosed within a membrane-bound organelle.

**3) Thylakoid**

In cyanobacteria, the photosynthetic pigments are found within the thylakoid membranes. Thylakoids are flattened, membrane-bound structures where the photosynthetic reactions occur. These membranes contain the pigment molecules, including chlorophyll a, phycocyanin, and phycoerythrin. The pigments are embedded in the thylakoid membrane, allowing them to capture light energy and transfer it to the reaction centers.

**4) Freely Present**

In addition to being present in the thylakoid membranes, cyanobacteria also contain photosynthetic pigments that are freely present in the cytoplasm. These pigments, such as carotenoids, are soluble in the cytoplasm and serve various functions in the photosynthetic process. Carotenoids help to protect the cyanobacteria from damage caused by excess light and oxidative stress. They also act as accessory pigments, transferring captured energy to the reaction centers.

Overall, the photosynthetic pigments in cyanobacteria are primarily found within the thylakoid membranes, where they capture light energy and facilitate the process of photosynthesis. Additionally, some pigments are freely present in the cytoplasm, serving protective and accessory roles. While cyanobacteria lack chloroplasts and chromatophores, they have evolved unique mechanisms to carry out photosynthesis and thrive in diverse environments.

As cynobacteria is prokaryotic cell there is no true plastids (like chloroplast)..... There are chromotophore structures in prokaryotic cell which posses pigments required to photosynthesis.... these chromotophores are analogous to thylakoid in eukaryotic cell as both have photosynthetic pigments but... but they are not thylakoids okk.