Cytoskeleton

Question 1

actin

Answer 1

Globular protein that links together to form long chains. Microfilaments are composed of two actin filaments twisted together in a helix.

Question 2

alpha-tubulin

Answer 2

One of two subunits in the molecule tubulin. The other subunit is a similar polypeptide called beta-tubulin. Microtubules are composed of tubulin.

Question 3

beta-tubulin

Answer 3

One of two subunits in the molecule tubulin. The other subunit is a similar polypeptide called alpha-tubulin. Microtubules are composed of tubulin.

Question 4

centriole

Answer 4

A component of the centrosome composed of a ring of nine microtubule triplets.

Question 5

cleavage furrow

Answer 5

The contractile ring of actin microfilaments and myosin that forms during cytokinesis, separating the parent cell into two daughter cells.

Question 6

cortex

Answer 6

A thin, cross-linked network of actin filaments lying immediately beneath the plasma membrane of animal cells.

Question 7

cytoplasmic streaming

Answer 7

Flow of cytosol and organelles; involves action of microfilaments.

Question 8

cytoskeleton

Answer 8

Internal framework of the cell; in eukaryotes, it is composed of microfilaments, intermediate filaments, and microtubules.

Question 9

depolymerization

Answer 9

Breakdown of a macromolecule through sequential removal of its component subunits.

Question 10

doublet

Answer 10

An aggregate of two microtubules.

Question 11

dynamic instability

Answer 11

Instantaneous occurrence of disassembly and assembly on the same site for cytoskeletal components.

Question 12

dynein

Answer 12

Motor protein associated with microtubules that enables movement of cilia and flagella.

Question 13

intermediate filament

Answer 13

One of the components of the cytoskeleton; composed of bundles of filamentous proteins. Provides support for cellular structures.

Question 14

kinesin

Answer 14

Motor protein associated with microtubules that enables movement of organelles and vesicles within the cytoplasm and separation of chromosomes during cell division.

Question 15

microfilament

Answer 15

A cytoskeletal component composed of two twisted actin filaments; the motor protein myosin enables movement of the microfilaments.

Question 16

microtubule

Answer 16

A cytoskeletal component made from tubulin. Each microfilament is a hollow rod.

Question 17

microtubule-organizing center (MTOC)

Answer 17

A structure that facilitates assembly of microtubules.

Question 18

mitotic spindle

Answer 18

Microtubule array that moves chromosomes during cell division.

Question 19

motor protein

Answer 19

A type of protein that interacts with microtubules or microfilaments and enables movement.

Question 20

myosin

Answer 20

Motor protein that is able to pull actin filaments together, resulting in contraction.

Question 21

nuclear lamina

Answer 21

Interior lining of the nucleus composed of intermediate filaments; maintains the shape of the nucleus and assists in nuclear function.

Question 22

polymerization

Answer 22

Assembly of a polymer from monomers.

Question 23

tubulin

Answer 23

Globular protein; dimers of alpha- and beta-tubulin form the hollow rods that compose microtubules