Certain micro- bodies exhibit specific biochemical characteristics as well as specific distributions among animal, plant, and microbial cells. Included here are the peroxisomes and glyoxysomes. Rhodin, who described the structure and properties of these organelles in mouse kidney tissue. Since then, organelles of similar organization have been reported in many other animal tissues and also in plants Fig. The chemical and enzymatic relationships between an oxidase, peroxidase, and catalase are shown in Figure The functions of peroxisomes in animal cells are diverse.
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Such structures are different from lysosomal vesicles because of their specific physiological properties; they are called micro bodies.
Their size varies from 0. The number also varies from 20 — per cell. In germinating seeds micro bodies increase in their number considerably. The contents of such structures may be amorphous, crystalline or fibrillar in nature. However, the enzymatic contents in them vary. Based on their functional properties they are classified into peroxisomes and glyoxysomes.
Peroxisomes Peroxisomes are characterized by their peroxidase activity. They are more or less dense spherical bodies bounded by a single unit membrane. The size is about 0. Almost every species in the plant kingdom contain peroxisomes in most of the cells. But among animals only higher vertebrates contain such structures. In higher plants, leaves of the C4 plants also contain micro bodies. They are mostly associated with plastids and mitochondria and they are mainly responsible for photo-respiration.
Fine dots are peroxisome. It also contains glycollate oxidase, glutamate glyoxylase, transaminases, other enzymes required for the breakdown of fatty acids. At least there are 32 known peroxisome proteins.
Peroxisomes assemble from derivative of ER vesicles and they replicate by fission. They are imported in unfolded condition. Once the proteins are delivered, they return to cytoplasm.
By what is called recycling mechanism or shuttle mechanism for which they require ATP input.
Biochemical Characteristics of Micro-bodies: Peroxisomes and Glyoxysomes (With Diagram)