Chapter 17 - Cytoskeleton

Which of the cytoskeletal structures are made up of protein subunits that are fibrous?

intermediate filaments

Which of the following is an important function of intermediate filaments?

providing tensile strength to the cell and the nucleus

How do the intermediate filament proteins keratin, vimentin, and neurofilaments differ from each other?

they are different at the head and tail domains that are exposed at the surface

In terms of structure, if cytoplasmic intermediate filaments are described as ropes, nuclear lamins could be best described as...

mesh

Microtubules extend from organizing centers in the cell. Which is an example of an organizing center?

basal body of a cilium

Microtubules are made up of 13 ____________ that are linear chains of __________

protofilaments, tubulin dimers

The end of the microtubule that has alpha-tubulin exposed is the ....

- end

Microtubules are inherently unstable unless they are...

stabilized by a +end attachment

Taxol and colchicine are used to treat cancer because they arrest dividing cells in mitosis. What is the mechanism of action of these drugs?

both drugs constrain the dynamic instability of microtubules

Microtubules participate in the spatial polarization of nerve cells because...

microtubule -ends originate near the cell body allowing +end directed transport along the axon

Which motor protein is an ATPase, has two globular heads, moves toward the -end of a microtubule, and generally interacts with cargo via an adaptor protein?

cytoplasmic dynein

Which of the following actin-binding proteins prevent polymerization of acting monomers?

thymosin and profilin

Which of the following motor proteins has one head domain, moves along actin toward the plus end, and is found in all cell types?

myosin-I

The binding of ATP causes a conformational change in myosin that ...

releases the myosin head from the actin filament