Centrioles
Definition:
Centrioles are small, cylindrical organelles found in most eukaryotic cells, involved in:
1. Microtubule organization
2. Cell division (mitosis and meiosis)
3. Cilia and flagella formation
4. Cellular structure and stability
Structure:
1. Composed of microtubules (9+0 or 9+2 arrangement)
2. Typically 0.2-0.5 μm in length and 0.1-0.2 μm in diameter
3. Paired centrioles (diplosome) connected by fibrils
Functions:
1. Microtubule nucleation and organization
2. Centrosome formation and regulation
3. Cilia and flagella assembly
4. Cell division (spindle fiber formation)
5. Intracellular transport and signaling
Types of Centrioles:
1. Primary centrioles (mother centriole)
2. Secondary centrioles (daughter centriole)
3. Basal bodies (modified centrioles in cilia and flagella)
Centriole Cycle:
1. Interphase: Centrioles duplicate and separate
2. Prophase: Centrioles migrate to poles
3. Metaphase: Spindle fibers form
4. Anaphase: Sister chromatids separate
5. Telophase: Centrioles return to interphase configuration
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27 окт 2024