Microtubule Dynamics and Structure Quiz

Microtubule Structure and Function

• Microtubules are found in many locations and have similar structures.
• Microtubules are composed of protein dimers (alpha and beta tubulin).
• Microtubules exhibit dynamic instability; that is, they grow and shrink in a cyclical manner.
• Microtubules grow preferentially at their plus ends.
• The plus end of microtubules is where new tubulin dimers are added.
• The minus end of microtubules is where tubulin dimers are lost.
• GTP-hydrolysis controls microtubule stability.
• Nucleation occurs at the minus end of microtubules by gamma tubulin ring complexes.
• Microtubules grow from the microtubule-organizing center (MTOC).
• Microtubule spacing depends on the length of the projection domain of microtubule-associated proteins.
• Different types of microtubules include singlet, doublet, and triplet microtubules.

Motor Proteins

• Kinesin and dynein are motor proteins that move along microtubules.
• Kinesin moves towards the plus end of the microtubules.
• Dynein moves towards the minus end of the microtubules.
• Motor proteins share similar domain structures: motor domain, ATPase, linker region, cargo domain.
• Dynein-dynactin complex is a minus-end-directed motor.
• Motor directionality can be determined by in vitro MT sliding assays.
• Kinesin-1 uses ATP to walk down a microtubule.

Microtubule Dynamics

• Dynamic instability of microtubules involves cycles of assembly and disassembly.
• Catastrophe is the rapid loss of tubulin dimers from the plus end.
• Rescue is the rapid addition of tubulin dimers to the plus end.
• GTP cap regulates microtubule stability.
• Photo-bleaching reveals the dynamic behavior of cytoskeletal filaments.

Microtubule-based Vesicle Transport

• DIC microscopy demonstrates microtubule-based vesicle transport.
• Organelles move on microtubules.
• Organelle transport by microtubule motors.

Cilia and Flagella

• Flagella propel cells through liquid.
• Cilia move material across the surface of cells.
• Flagella and cilia are comprised of microtubules.

Mitosis

• Mitosis is a part of the cell cycle.
• Mitosis in an animal cell and related structure and function were discussed.

Other Notable Information

• Gamma-tubulin ring complexes nucleate microtubules at the minus end.
• MAP2 and tau regulate microtubule spacing.
• Katanin severs microtubules.
• Hook decoration method for visualizing microtubules.

Test your understanding of microtubule structure and dynamics with this quiz. Explore topics such as nucleation sites, subunit composition, and the roles of microtubule-associated proteins. Enhance your knowledge of the mechanisms that regulate microtubule stability and dynamics.