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Alginic acid: It is a common polysaccharide in the cell walls of brown algae. Sulfonated polysaccharides: They occur in the cell walls of most algae; those common in red algae include agarose, carrageenan, porphyran, furcelleran and funoran. Other compounds that may accumulate in algal cell walls include sporopollenin and calcium ions.
They have cellulose walls with alginic acid and also contain the polysaccharide fucoidan in the amorphous sections of their cell walls. A few species (of Padina) calcify with aragonite needles. [26] In addition to alginates, fucoidan and cellulose, the carbohydrate composition of brown algae consists of mannitol, laminarin and glucan. [52]
The structural role of phlorotannins in brown algal cell wall is a primary role of these polyphenolic compounds. [7] [13] This primary role may however not be the main role of the phlorotannins, since studies show they are more abundant in cytoplasm or in the exuded form than in cell wall. [28]
Diatom cells are contained within a unique silica cell wall known as a frustule made up of two valves called thecae, that typically overlap one another. [41] The biogenic silica composing the cell wall is synthesised intracellularly by the polymerisation of silicic acid monomers. This material is then extruded to the cell exterior and added to ...
An NMR analysis of whole algal cells which were cultivated in autotrophic growth [18] reports evidence of the presence of cellulose in the cell wall and of mobile chrysolaminarin, probably accumulated in solution in vacuoles inside the cell.
Red algal morphology is diverse ranging from unicellular forms to complex parenchymatous and non- parenchymatous thallus. [44] Red algae have double cell walls. [45] The outer layers contain the polysaccharides agarose and agaropectin that can be extracted from the cell walls as agar by boiling. [45] The internal walls are mostly cellulose. [45]
The structure of these algae is unicellular, and lacks flagella.Although most desmid species are unicellular, some genera form chains of cells, called filaments. A few genera form non-filamentous colonies, with individual cells connected by threads or remnants of parent cell walls.
The chlorophyte and charophyte green algae and the embryophytes or land plants form a clade called the green plants or Viridiplantae, that is united among other things by the absence of phycobilins, the presence of chlorophyll a and chlorophyll b, cellulose in the cell wall and the use of starch, stored in the plastids, as a storage polysaccharide.