What are the demerits of fritsch system of Algal classification
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Type # 1. Nuclear Organization:
On the basis of nuclear organization algae can be prokaryotic or eukaryotic. Cyanophyceae or blue green algae are prokaryotic in nature whereas all other classes of algae are eukaryotic. In prokaryotic e.g., Cyanophyceae—nucleus is not organized as nuclear membrane is absent.
DNA fibrils are free in nucleoplasm and are not associated with histones. Cell division by mitosis and meiosis is not found. Membrane bound cell organelle like chloroplast, mitochondria and ER are absent. Eukaryotic algae have well differentiated nucleus, mitochondria, chloroplast and endoplasmic reticulum in their cell structure.
Type 2
The cell wall in algae is generally made up of polysaccharides. In some cases lipids and proteins are also present in them. The inner layer of cell wall in algae is generally made up of cellulose, which is insoluble polysaccharide and the outer layer is made of pectic substances.
The cell wall in Chlorophyceae is made up of cellulose. In Xanthophyceae pectic substance is more common.
In Chrysophyceae cell wall is non-cellulosic which is silicified or calcified. In Phaeophyceae cell wall contains alginic acid and fucinic acid. In Rhodophyceae the cell wall is made of non-cellulosic polysaccharides like xylans and galactans. In Cyanophyceae or blue green algae the cell wall is more like bacteria and is made up of mucopeptides.
Type # 3. Pigmentation and Photosynthetic Apparatus:
The pigment is one of the most important criteria used in differentiation of classes in algae, as algae were initially and primarily separated on the basis of colour e.g., green algae, red algae, brown algae or blue-green algae. The pigments in algae can be chlorophylls, carotenoids and biloproteins.
On the basis of nuclear organization algae can be prokaryotic or eukaryotic. Cyanophyceae or blue green algae are prokaryotic in nature whereas all other classes of algae are eukaryotic. In prokaryotic e.g., Cyanophyceae—nucleus is not organized as nuclear membrane is absent.
DNA fibrils are free in nucleoplasm and are not associated with histones. Cell division by mitosis and meiosis is not found. Membrane bound cell organelle like chloroplast, mitochondria and ER are absent. Eukaryotic algae have well differentiated nucleus, mitochondria, chloroplast and endoplasmic reticulum in their cell structure.
Type 2
The cell wall in algae is generally made up of polysaccharides. In some cases lipids and proteins are also present in them. The inner layer of cell wall in algae is generally made up of cellulose, which is insoluble polysaccharide and the outer layer is made of pectic substances.
The cell wall in Chlorophyceae is made up of cellulose. In Xanthophyceae pectic substance is more common.
In Chrysophyceae cell wall is non-cellulosic which is silicified or calcified. In Phaeophyceae cell wall contains alginic acid and fucinic acid. In Rhodophyceae the cell wall is made of non-cellulosic polysaccharides like xylans and galactans. In Cyanophyceae or blue green algae the cell wall is more like bacteria and is made up of mucopeptides.
Type # 3. Pigmentation and Photosynthetic Apparatus:
The pigment is one of the most important criteria used in differentiation of classes in algae, as algae were initially and primarily separated on the basis of colour e.g., green algae, red algae, brown algae or blue-green algae. The pigments in algae can be chlorophylls, carotenoids and biloproteins.
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