Chapter 9: The Cytoskeleton And Cell Motility

Front 1

What is the cytoskeleton?

Back 1

A network of filamentous structures: microtubules, microfilaments, and intermediate filaments.

Front 2

Roles of the cytoskeleton:

Back 2

Serves as a scaffold providing structural support and maintaining cell shape

Serves as an internal framework to organize organelles within the cell

Directs cellular locomotion and the movement of materials within the cell

Provides anchoring site for mRNA

Serves as a signal transducer

Essential component of the cell's division machinery

Front 3

The microtubule is a set of globular proteins arranged in longitudinal rows called _______________

Back 3

protofilaments

Front 4

Microtubule nucleation occurs perinuclear at the _______________

Back 4

centrosome

Front 5

Outer microtubules in a cilia and flagella are generated at a structure known as the ________________

Back 5

basal body

Front 6

Plant cells lack MTOCs; their microtubules are organized around the ___________

Back 6

nucleus

Front 7

Microtubule nucleation

Back 7

role of y-tubulin in centrosome function

Front 8

MTOCs control the ___________________, __________, _______________, and __________________

Back 8

number of microtubules, their polarity, the number of protofilaments, and the time and location of their assembly

Front 9

The protein y-tubulin is found in all MTOCs and is critical for _______________

Back 9

MT nucleation

Front 10

4 distinct arrays of microtubules in a dividing plant cell

Back 10

Widely distributed throughout the cortex

Making a single transverse band

In the form of a mitotic spindle

As a phargmoplast assisting in the formation of the cell wall of daughter cells

Front 11

Cilia and Flagella

Back 11

hair-like motile organelles

Front 12

Microtubule-Associated Proteins (MAPS)

Back 12

comprise a heterogeneous group of proteins

attach to the surface of microtubules to increase their stability and promote their assembly

regulated by phosohorylation of specific amino acid residues

Front 13

Microtubules as structural supports and organizers

Back 13

the distribution of microtubules determines the shape of the cell

microtubules maintain the internal organization of cells

microtubules function in axonal transport

microtubules play a role in axonal growth during embryogenesis

Front 14

Axonal transport

Back 14

Movement of neurotransmitters across the cell

Movement away from the cell body and toward the cell body

Mediate tracks for a variety of motor proteins

Front 15

Kinesin

Back 15

Member of a superfamily called Kinesin-like proteins

Front 16

Dynein

Back 16

Responsible for the movement of cilia and flagella

Front 17

Cytoplasmic dynein

Back 17

Huge protein with a globular, force-generating head

Front 18

MTOCs

Back 18

specialized structures for the nucleation of microtubules

Front 19

Centrosome

Back 19

structures responsible for initiating microtubules in animal cells

Front 20

intraflagellar transport

Back 20

the process responsible for assembling and maintaining flagella

Front 21

Ciliary dynein

Back 21

required for ATP hydrolysis, which supplies energy for locomotion

Front 22

Intermediate filaments Assembly:

Back 22

basic building block is a rod-like tetramer formed by two antiparallel dimers

both the tetramer and the IF lack polarity

Front 23

Intermediate Filaments include __________, which are the major component of the network supporting neurons

Back 23

Neurofilaments

Front 24

Microfilaments are composed of actin and are inolved in __________

Back 24

cell motility

Front 25

Skeletal muscle fiber

Back 25

a multinucleate cell as a result of fusion of myoblasts in the embryo

Front 26

Each muscle fiber contains hundreds of cylindrical strands called

Back 26

Myofibrils

Front 27

Each myofibril consists of a repeating array of

Back 27

sarcomeres

Front 28

Contact between nerve and muscle is called the

Back 28

neuromuscular junction

Front 29

The linking of the nerve impulse to the shortening of the sarcomere is referred to as

Back 29

excitation-contraction coupling

Front 30

Action potential in muscles is propagated into the cell interior by

Back 30

transverse tubules

Front 31

Actin-binding proteins

Back 31

affect the localized assembly or disassembly of the actin filaments