1. Dr Mah Jabeen Muneera Assistant Professor Department of Anatomy KEMU

2. Importance Microtubules Microfilaments Intermediate filaments

4. shape: hollow cylinders Diameter: 20-25nm Basic protein subunit: Dimers of α and β tubulin

5. polarity: _ (minus) end is non growing and + end is the growing end Dynamic instability: Polymerization and depolymerization Stable microtubules in cilia and flagella

8. Immotile cilia syndrome Mutations in dyenin protein Respiratory tract infections and infertility

9. Centrosome: Centrioles and pericentriolar material Centrioles provide basal bodies for cilia and flagella

10. An amorphous protein matrix with an abundance of tubulin rings. Each tubulin ring serves as the nucleation site for the growth of a single microtubule. Minus (–) end of the microtubule remains attached to the MTOC, and the plus end represents the growing end directed toward the plasma membrane.

13. In the absence of centrioles, astral microtubules fail to develop, causing errors in mitotic spindle formation.

14. Colchicine Prevents polymerization 1.It binds specifically to tubulin 2.Tubulin-colchicine complex binds to microtubules 3. TC complex prevents the addition of more tubulin in the plus extremity used to prepare karyotype treatment of acute stages of gout Karyotype

15. Taxol – accelerates polymerization and prevent depolymerization thus stabilizing microtubules - cancer chemotherapy Vinblastine and Vincristine- accelerates depolymerization and form paracrystalline arrays - cancer chemotherapy

16. MAPs 1,2,3,4 stabilize microtubules Motor proteins- dyneins and kinesins- required for organelle movement