Cytoskeleton

Question 1

What is the cytoskeleton?

Answer 1

Network of filaments that spread through eukaryotic cells

Question 2

What 3 things does the cytoskeleton provide?

Answer 2

Shape
Internal organisation
Functional polarity

Question 3

What is the cytoskeleton responsible for?

Answer 3

cell movement, shape, contraction
organelle movement and distribution, vesicle transport
Chromosome separation at mitosis
Separation of daughter cells

Question 4

What are the 3 independent protein networks that make up the cytoskeleton?

Answer 4

Microfilaments
Microtubules
Intermediate filaments

Question 5

Describe actin, microtubules and intermediate dilaments in terms of their size

Answer 5

Actin 7-9 nm
Microtubules 25nm
Intermediate filaments 10nm

Question 6

Describe microfilaments

Answer 6

Polymers of actin organised into functional bundles and networks. Important in the organisation of the plasma membrane, give shape to surface structures (microvilli)

Question 7

Describe microtubules

Answer 7

Long tubes formed by tubulin and organised by microtubule associated proteins. Extend throughout the cell to provide an organisational framework for associated organelles and structural support for cilia/flagella. Make up the structure of the mitotic spindle. Motor proteins transport substances along microtubules using ATP.

Question 8

Intermediate filaments

Answer 8

Tissue specific filamentous structures that provide cell integrity and have barrier functions in the skin.

Question 9

Describe the steps in the regulation of cytoskeletal function

Answer 9

Signals from soluble factors bind to surface receptors. These signals are transmitted across the plasma membrane to activate specific cytosolic signalling pathways. Signals are integrated to organise the cytoskeleton