2.1.8 The Cytoskeleton

Question 1

The Cytoskeleton

Answer 1

Within the cytoplasm of cells, there is an extensive network of protein fibres
- this is known as the cytoskeleton
The cytoskeleton is made up of 2 main types of proteins fibres: microfilaments and microtubules
- microfilaments are solid strands that are mostly made of the protein actin - these fibres can cause some cell movement and the movement of some organelles within cells by moving against each other
- microtubules are tubular (hollow) strands that are mostly made of the protein tubulin - organelles and other cell contents are moved along these fibres using ATP to drive this movement
Intermediate filaments (a third type of fibre) are also found within the cytoskeleton

Question 2

The Importance of the Cytoskeleton

Answer 2

The cytoskeleton is important as it has several different functions, including:
Support
- 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
Intracellular (within cell) Movement
- 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 cells during cell division
Cellular Movement
- the cytoskeleton enables cell movement via cilia and flagella
- these structures are hair-like extensions that protrude from the cell surface and contain microtubules that are responsible for moving them