Lecture14 - Cytoskeleton_ tubulin 2.pptx (1)

What are microtubules made of?

Microtubules are made of alpha and beta tubulin heterodimers.

What is the term for the change from growth to shrinkage in microtubules?

Catastrophe.

What is dynamic instability in microtubules?

Dynamic instability is a process in which individual microtubules alternate between cycles of growth and shrinkage.

What motor proteins move towards the plus ends of microtubules?

Kinesins.

What is the composition of kinesin protein?

Kinesin is a tetramer protein made up of two heavy chains and two light chains.

How many tubulin monomers does the step size of kinesin correspond to?

The step size of kinesin corresponds to four tubulin monomers.

What technique can be used to observe kinesin dynamics?

Kinesin in-vitro motility assay.

What are kinesin-13 proteins known for?

Kinesin-13 proteins are microtubule depolymerases that induce depolymerization from both ends of the microtubule.

What does cytoplasmic dynein move toward?

Cytoplasmic dynein moves toward the minus ends of microtubules.

How does the tail of kinesin contribute to its function?

The tail of kinesin binds cargo.

What are the main differences between dynein and kinesin?

Dynein is larger and moves towards the minus end, while kinesin is smaller and moves towards the plus end.

How do motor proteins affect the transport of vesicles in the secretory pathway?

Kinesin-mediated and dynein-mediated transport facilitate the movement of vesicles, vesicular-tubular clusters, and organelles.

What role do melanosomes play in the cell?

Melanosomes synthesize and store melanin and their movement is mediated by dynamin and microtubules.

What is the axoneme?

The axoneme is the core of cilia and flagella, composed of microtubules and their associated proteins.

What structure causes the bending of the axoneme?

Axonemal dynein bends the axoneme, which moves the cilium and flagellum.

What characterizes kinesin's movement?

Kinesin exhibits progressive movement towards the plus end.

What are some functions associated with dynein?

Dynein is involved in organelle transport, axonal transport, and linkage to the secretory pathway.