Lecture No 14 PEROXSOME AND GLYXISOME скачать в хорошем качестве

Lecture No 14 PEROXSOME AND GLYXISOME

Peroxisome A peroxisome is a small, membrane-bound organelle found in eukaryotic cells (both plant and animal cells). It is mainly involved in oxidative reactions. Structure • Surrounded by a single membrane • Contains oxidative enzymes such as oxidases and catalase • Does not contain DNA or ribosomes • Enzymes are synthesized in the cytoplasm and imported into the peroxisome Functions • Breakdown of fatty acids (β-oxidation), especially very long-chain fatty acids • Detoxification of harmful substances like alcohol and hydrogen peroxide • Metabolism of hydrogen peroxide (H₂O₂) • Oxidases produce H₂O₂ • Catalase converts H₂O₂ into water and oxygen • In plants: role in photorespiration Importance Peroxisomes protect cells from oxidative damage and help maintain metabolic balance. ⸻ Glyoxysome A glyoxysome is a specialized type of peroxisome found mainly in germinating seeds of plants. It plays a crucial role in fat metabolism during seed germination. Structure • Surrounded by a single membrane • Contains enzymes of fatty acid β-oxidation • Contains key enzymes of the glyoxylate cycle (e.g., isocitrate lyase, malate synthase) Functions • Converts stored fats into carbohydrates • Enables synthesis of glucose from fatty acids • Provides energy and carbon skeletons for the growing seedling before photos