Ch 6: The Cytoskeleton and Cell Motility

Question 1

What are the functions of cytoskeleton?

Answer 1

①providing structural support
②positioning the various organelles within the cell
③direct the movement of materials and organelles within the cells
④moves cells from one place to another

Question 2

What is the structure of microtubule?

Answer 2

A hollow、tubular structure，with an outer diameter of 25nm，and thickness of 4nm

Question 3

What are the functions of MAPs?

Answer 3

Microtubule-associated proteins（MAPs） increase the stability of microtubules and promote their assembly

Question 4

What are the two groups of microtubule motor proteins? What are their walking directions and functions?

Answer 4

Kinesin & dynein
Kinesin - plus end directed microtubular motor
Dynein - minus end directed microtubular motor
Function-
generateforce required to move along microtubule rack
mediated organelle transport

Question 5

concept

MTOC- Microtubule-organizing centers

Answer 5

a variety of specialized structures that, because of their role in initiating microtubule formation, are called MTOC.

Question 6

concept

g-TuRC- g-tubulin ring complex- γ-Tubulin

Answer 6

member of the tubulin family, is important in the nucleation and polar orientation of microtubules. It is found primarily in centrosomes and spindle pole bodies.

Question 7

Where do basal bodies come from in a cell with cilia or flagella?

Answer 7

at the base of the cilium or flagellum

Question 8

What are the two mechanisms resulting in spatial change of microtubules?

Answer 8

the rearrangement of existing microtubules

‚the disassembly of existing microtubules and reassembly of new ones in different regions of the cell

Question 9

What is the structure of intermediate filament?

Answer 9

Intermediate filaments（IFs）are solid、unbranched filaments with a diameter of approximately 10nm. IFs are strong, ropelike fiber, often interconnected to the other types of cytoskeletal filaments by thin cross-bridges

Question 10

What is the structure of microfilament?

Answer 10

Microfilaments are 8nm in diameter and composed of globular subunits of the protein actin

Question 11

What kinds of cytoskeleton have treadmilling?

Answer 11

Microtubule and microfilament

Question 12

Which kind of myosin is responsible for muscle contraction?

Answer 12

Myosin II