2.1.8 Cytoskeleton

Question 1

what is the cytoskeleton? structure

Answer 1

an extensive network of protein fibres, in the cytoplasm

Question 2

what are the two main types of protein fibres that make up the cytoskeleton?

Answer 2

microfilaments and microtubules (also intermediate filaments)

Question 3

what are microfilaments? structure

Answer 3

microfilaments are solid strands that are mostly made of the protein actin.

Question 4

what are microfilaments? function

Answer 4

these fibres can cause some cell movement and the movement of some organelles within cells by moving against each other

Question 5

what are microtubules? structure

Answer 5

microtubules are tubular (hollow) strands that are mostly made of the protein tubulin.

Question 6

what are microtubules? function

Answer 6

organelles and other cell contents are moved along these fibres using ATP to drive this movement

Question 7

what are the three functions of the cytoskeleton?

Answer 7

-strengthening and support
-intracellular movement
-cellular movement

Question 8

explain the strengthening and support function

Answer 8

the cytoskeleton provides the cell with mechanical strength, forming a kind of ‘scaffolding’ that helps to maintain the shape of the cell
it also supports the organelles, keeping them in position

Question 9

explain the intracellular movement function

Answer 9

the cytoskeleton aids transport within cells by forming ‘tracks’ along which organelles can move
examples of this include the movement of vesicles and the movement of chromosomes to opposite ends of a cell during cell division

Question 10

explain the cellular movement function

Answer 10

the cytoskeleton enables cell movement via cilia and flagella
these structures are both hair-like extensions that protrude from the cell surface and contain microtubules that are responsible for moving them

Question 11

what is the overall function of the cytoskeleton?

Answer 11

the cytoskeleton provides mechanical strength to cells, aids transport within cells and enables cell movement

Question 12

what are microfilaments made of?

Answer 12

actin

Question 13

what are microtubules made of?

Answer 13

tubular

Question 14

where are microtubules found?

Answer 14

in all eukaryotic cells

Question 15

how are microtubules made?

Answer 15

made of α and β tubulin combined to form dimers, the dimers are then joined into protofilaments
thirteen protofilaments in a cylinder make a microtubule

Question 16

how many protofilaments in a cylinder make a microtubule?

Answer 16

thirteen