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.

4. •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.

5. •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 μm in diameter
• Also found in Protozoa, Yeast and higher plants.

6. •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.

7. •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.

9. •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.

10. •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