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| Diagrammatic representation of a prochlorophyte cell. |
| The Cyanobacteria | page 5 |
The Prochlorophyta
Characteristics
of Cyanobacteria |
|
| Main pigments |
Chlorophyll-a + Chlorophyll-b, ß Carotene, Zeaxanthan, Cryptoxanthin, phycobiliprotein pigments absent |
| Nuclear material |
DNA is free in the cytoplasm and is not enclosed in a membrane, it is not central as in Cyanophyta but is rather diffuse throughout the cell. |
| Food reserves | Cyanophycean starch; cyanophycin granules are absent |
| Chloroplast features | Chloroplast absent; the thylakoids are free in the cytoplasm and stacked in groups of two or more; phycobilisomes absent |
| Cell wall | Four-layered peptidoglycan wall in which murein is the principal component |
| Flagella | Absent |
A new organism discovered in the 1970s, and it created quite a sensation because of its similarities to the green plant chloroplast. A new Division of prokaryotic algae was erected, and named the Prochlorophyta. Unlike the Cyanobacteria they contain the additional photosynthetic pigment, chlorophyll-b and they lack the phycobiliprotein pigments. Their nuclear material is more scattered than in the Cyanophyta. There is no chloroplast as is characteristic of prokaryotes but, unlike in the cyanophytes, the thylakoids are stacked in groups of two or more as is the case with eukaryotic green plants. The food reserve is cyanophycean starch, and unlike the bluegreens, cyanophycin granules are absent. Cell wall features are as in the cyanophytes, and they have no flagellated stages. Sexual reproduction remains unknown.
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| Diagrammatic representation of a prochlorophyte cell. |
