Peroxisomes, glyoxysomes, vacuole, cytoskeleton,

Peroxisomes, glyoxysomes, vacuole, cytoskeleton,

1. Peroxisomes, Glyoxysomes, Vacuole, Cytoskeleton, centriole 30 NOV

2. PEROXISOMES: Discovered by De Duve and his coworkers in 1965. They isolated these particles from liver cells of eukaryotic organisms. They contain enzymes that oxidize certain molecules normally found in the cell, notably fatty acids and amino acids. Those oxidation reactions produce hydrogen peroxide, which is the basis of the name peroxisome.

3. ENZYMES: They contain enzymes like: Peroxidase Catalase Glycolic acid oxidase And some other enzymes This organelle is specified for formation and decomposition of hydrogen peroxide in cell.

4. STRUCTURE AND COMPOSITION: They are enclosed in single membrane, Present in both plants and in animals, Contain hydrogen peroxide producing oxidases and catalases (enzymes). They are 0.5 μ m in diameter Also found in Protozoa, Yeast and higher plants.

5. GLYOXYSOMES: Only present in plants. Most abundant in plant seedlings for the breakdown of stored fatty acid to provide energy to growing plant embryo. It’s primary function in seedlings is to convert stored fatty acid into the carbohydrates. This conversion takes place by GLYOXYLATE CYCLE in which the enzymes in the glyoxysomes convert fatty acid into carbohydrates.

6. FUNCTION: Play important role in catabolic and anabolic pathways. In seeds rich in fatty acids like castor bean, soya bean glyoxysomes breakdown fatty acid into succinate(carbohydrate). Only present in seeds rich in fatty acid and present for short time (seed life) to help in germination of seed. It is absent lipid poor seeds.

7. VACUOLES: Present in both animals and plants. Large and abundant in Plant cell and occupy most of cell’s space forcing other organelles to the peripheral areas of cells. Bound by single membrane. In plant the large vacuole form in result of fusion of many small vacuoles during plant cell growth and development.

8. FUNCTION of PLANT VACOULE: They serve to expand plant cell without diluting it’s cytoplasm Act as storage site for water and solutes of cell. Provides turgidity to plant cell Provide rigidity to young leafs and younger parts of plants. It fills itself with water and automatically size of cell increases . Swelling of cell to maintain its shape