Unit 1: The Cytoskeleton

Question 1

The cytoskeleton is an intricate, interconnected system of

Answer 1

protein filaments

Question 2

The cytoskeleton is found only in what type of cell?

Answer 2

Eukaryotic

Question 3

What is the purpose of the cytoskeleton?

Answer 3

To provide a framework of mechanical support to a cell allowing it to maintain its shape.

Question 4

In cell division, the cytoskeleton is responsible for the movement of

Answer 4

chromosomes during meiosis and mitosis and the division of the cytoplasm during cytokinesis

Question 5

What are the three parts of the cytoskeleton?

Answer 5

Actin filaments, Intermediate filaments and microtubules

Question 6

What is the structure of actin filaments?

Answer 6

Two stranded helical chains of actin monomers

Question 7

How are actin filaments arranged?

Answer 7

In linear bundles or networks

Question 8

Networks of actin filaments help to do what?

Answer 8

Reinforce cell surface

Question 9

What is the role of Actin filaments in cytokinesis?

Answer 9

Restructuring the cell surface

Question 10

Actin filaments are also involved in ______ contraction

Answer 10

muscle

Question 11

What is the structure of Intermediate filaments ?

Answer 11

Rope like fibres made up of fibrous proteins

Question 12

What is the role of intermediate filaments?

Answer 12

Involved in the maintenance of the shape of cells or parts of cells including the nuclear envelope

Question 13

An example of an intermediate filament is a ?

Answer 13

Lamin

Question 14

Lamins are intermediate filaments that form a

Answer 14

meshwork called a nuclear lamina which reinforces the nuclear envelope

Question 15

Microtubules are the largest _____ of the cytoskeleton

Answer 15

element

Question 16

What is the structure of a microtubule?

Answer 16

Hollow cylinders composed of monomers of tubulin proteins

Question 17

Alpha tubulin molecules join Beta tubulin molecules to form

Answer 17

tubulin heterodimers

Question 18

Microtubules are dynamic structures that come form the

Answer 18

MTOC, microtubule organising centre

Question 19

Animals have a single well defined MTOC called a

Answer 19

centrosome

Question 20

A centrosome is

Answer 20

a microtubule organising centre

Question 21

Microtubules are produced by a

Answer 21

MTOC which in animals is a centrosome

Question 22

Microtubules form a network of intracellular railway tracks along which transport of

Answer 22

organelles occurs

Question 23

Kinesin Motor Protein: Stage 1, Two kinase motorheads like a cherry with the organelle at the other end, one swings forward and attaches to a

Answer 23

microtubule

Question 24

Kinesin Motor Protein: Stage 2, microtubule binding causes the release of

Answer 24

ADP

Question 25

Kinesin Motor Protein: Stage 3, ATP is then rapidly introduced back to the moorhead and binds, this causes the other motorhead to

Answer 25

swing forward and attach to the microtubule track.

Question 26

Microtubules form what important component of meiosis?

Answer 26

Spindle fibres