. The function of polysomes is the formation of several copies of a particular polypeptide during protein synthesis. They Figure . : Structure of Chloroplast .
. Microbodies Eukaryotic cells contain many enzyme bearing membrane enclosed vesicles called microbodies . They are single unit membrane bound cell organelles. Example: Peroxisomes and glyoxysomes.
. . Peroxisomes Figure . : Structure of Peroxisome Peroxisomes were identified as organelles by Christian de Duve ( ).
Peroxisomes are small spherical bodies and single membrane bound organelle. It takes part in photorespiration and associated with glycolate metabolism. In plants, leaf cells have many peroxisomes. It is also commonly found in liver and kidney of mammals.
These are also found in cells of protozoa and yeast (Figure . ). . .
Glyoxysomes Glyoxysome was discovered by Harry Beevers ( ). It is a single membrane bound organelle. It is a sub cellular organelle and contains enzymes of glyoxylate pathway. β-oxidation of fatty acid occurs in glyoxysomes of germinating seeds Example: Castor seeds.
. . Sphaerosomes It is spherical in shape and enclosed by single unit membrane. Example: Storage of fat in the endosperm cells of oil seeds.
. . Centrioles Centrioles consists of nine triplet peripheral fibrils made up of tubulin. The central part of the centriole is called hub , is connected to the tubules of the peripheral triplets by radial spokes ( + pattern).
The centriole form the basal body of cilia or flagella and spindle fibers which forms the spindle apparatus in animal They contain a variety of hydrolytic enzymes, that can digest material within the cell. The membrane around lysosome prevent these enzymes from digesting the cell itself (Figure . ). Figure .
: Structure of Lysosome Functions: • Intracellular digestion: They digest carbohydrates, proteins and lipids present in cytoplasm. • Autophagy: During adverse condition they digest their own cell organelles like mitochondria and endoplasmic reticulum • Autolysis: Lysosome causes self destruction of cell. • Ageing: Lysosomes have autolytic enzymes that disrupts intracellular molecules. Acid Hydrolases Nuclease, Proteases Glycosidases Lipases Phophatases Sulphatases Phospholipidases pH .
ATP ADP + iP Enzymes of Lysosome Figure . : Enzymes of Lysosome • Phagocytosis: