Overview
This lecture explains the structure and essential functions of centrioles in animal cells, highlighting their roles in microtubule organization, cell division, and the formation of cilia and flagella.
Structure of Centrioles
- Centrioles are cylindrical, microtubule-based structures found in animal cells.
- They are usually present in pairs near the nucleus within a region called the centrosome.
- Each centriole consists of nine sets of triple microtubules arranged in a barrel-like cylinder.
- Centrioles exist as a mother (older) and daughter (newer) pair.
- The mother centriole serves as a template for the daughter centriole.
- Together, they form the centrosome, the cell's microtubule organizing center.
Functions of Centrioles
- Centrioles organize microtubules, which are protein filaments forming the cell’s cytoskeleton.
- They help nucleate and anchor microtubules, maintaining the cell’s structure.
- During cell division (mitosis and meiosis), centrioles form the mitotic spindle for chromosome segregation.
- Spindle fibers emerge from centrioles, ensuring accurate genetic material distribution.
- Centrioles help form cilia and flagella, acting as basal bodies to create their core structure (axoneme).
- Cilia and flagella enable cell movement and sensory functions.
- Centrioles organize microtubule tracks for motor proteins (dynein, kinesin) to move cargo inside the cell.
Key Terms & Definitions
- Centriole — Cylindrical structure made of nine sets of triple microtubules, found in animal cells.
- Centrosome — Organelle near the nucleus containing a pair of centrioles; serves as the microtubule organizing center.
- Microtubule — Protein filament forming part of the cytoskeleton, providing structure and pathways for transport.
- Mitotic spindle — Structure formed by microtubules for separating chromosomes during cell division.
- Basal body — A centriole functioning as the foundation for cilia and flagella formation.
- Axoneme — Central structural core of cilia and flagella, built from microtubule doublets.
- Motor proteins — Proteins (dynein, kinesin) that move along microtubules to transport cellular materials.
Action Items / Next Steps
- Review functions and structure of centrioles for exams.
- Learn more about other cell organelles as suggested in further readings or playlists.