(1) Chlorophyll: It is green colouring matter and is photosynthetic pigment. Chlorophyll is not present in cyanochlorapta. Pigments in algal cells are contained in plastids or chromatophores which vary in shape in different groups. When plastic is rich in chlorophyll it is called chloroplast.
(2) Carotenoid: They are unsaturated hydrocarbons and are of two types (i) Carotenes and (ii) Xanthophylls. About five different carotenes are found in algal cells. There is large number of xanthophylls in present in algal cells. Xanthophylls include Peridin, Myxoxanthin, Tetraxanthin, Anthraxanthin and Fucoxanthin.
(3) Biloprotein: They are water soluble and are present in Cryptophyta, Cyanochloranta and Rhodophyta and are of two types called phycocyanin and phycoerythrin.
Classification: Important cases of Algae are:
Class (1) Chlorophycrae (green algae): Pigments are present in plastids or chromatophores. Pigments are chlorophyll, xanthophylls and carotene. Starch is photosynthetic food product, but rarely oil as in vaucheria. In chromatophores pyrenoids are present. Both flagella are equal in length i.e. they are isokonate. Majority of genera live in fresh water and few live in marine water. Cell wall is of cellulose e.g. chlamydononas, char, vaucheria, volvox, cladophora, stigiocloxeum, ulothrix and chlorena.
Class (2) Rhodophyceae: They are called red algae chrometophores possess red pigment. Reserve food material is Polysaccharides starch and soluble sugar. They are non motile i.e. flagella re absent. Mostly marine and few are fresh water. Sexual reproduction is speciality and advanced e.g. Polysiphonia, Batrochospermum.
Class (3) Pharophycrae: They are called brown algae. Plants seem to be yellow brown in colour. Chromatophores are yellow brown in colour. Reserve food products are alcohols, mannitol and Lamixarine. Motile reproductive cells are pyriform with tow laterally inserted flagella. Always multicellular plant body is present. They are mostly marine and rarely fresh water. Zygote has no resting period. E.g. Fucus, Ectocarpus.
Class (4) Myxophyceae: They are blue green algae. There are mostly fresh water and few marine. Pigments are present in peripheral portion of protoplast. Plants are blue green due to pigment C-phycocyanin. Reserve food products are sugars and glycogen like compounds cells cynophecean starch. Flagella are absent sexual reproduction is unknown. Mynophyceae is also called cyanophyceae or schizophyceae e.g. oscillatoria, Nostoc.
Class (5) Xanthophyceae: They are called yellow green algae. Principal reserve is oil. Their biochemical features are shared by heterogenous assortment of species, the relationships between which are not close e.g. Vaucheria, Plumularia.
Class (6) Bacillariophyceae: They are commonly called Diatoms. They have some biochemical simitiarities xanthophyceae. In both groups carotenoid pigments give individuals a yellowish colour and in both reserves is oil. But unique type of cell structure among diatoms justifies being placed in separate calls. E.g. Diatoms. Class (7) Euglenophyceae: They are common in fresh water and are formed of a single cell. Body is elongated. Cell wall is absent. A thread or whip like flagellum is present for locomotion. They are a group of flagellated micro organisms. Many species have photosynthetic pigments similar to higher plants and are partly auto tropic e.g. Euglena, Astrasia, Anisonema.
Class (8) Chrysophyceae: They are called brown or orange Algae. Phycocheysin is dominant pigment which gives brown or orange colour to Algae plants. Chronatophore has naked pyrenoid bodies. Food reserve is chrysolaninarim and lencosin. Cell wall is cilified or calcified with no cellulose. There are two equal or unequal flagella. Sexual reproduction is rare, if present it is isogamous e.g. chrysallonium, chrysococcus, chrysopsphaera.
Class (9) Chloromonadinae: They provide bright tint due to excess of xanthophylls. Reserve food is fat and oil. Pyrenoids are absent. Two equal flagella are present. Sexual reproduction is absent e.g. Trentonia, Vacuolaria.
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