Cytoskeleton

Question 1

The function of the Cytoskeleton?

Answer 1

Connects with the extracellular matrix, allows cytokinesis, maintains cell shape, allows for cell movement, allows intracellular transport and allows chromosome seperation

Question 2

What are Actin Microfilaments?

Answer 2

They have a G-actin monomer which polymerises to microfilament F-actin with ATP hydrolysis
Monomers lead head to tail
Has dynamic structure as the length depends on the rate of loss or gain of G-actin
Consists of two light chains with G and F actin binding round each other

Question 3

Function of Actin?

Answer 3

Allows for muscle contraction, mechanical support, maintaining the cells shape and allowing cell movement

Question 4

What are the 3 actin binding proteins?

Answer 4

G-actin binding proteins, cross linking proteins and severing proteins

Question 5

Intermediate filament proteins?

Answer 5

Epithelial cells for physical and external structures
Neurofilaments for structural arrangement of axons
Nuclear Lamins (A,B,C) support nuclear structure, lamins are not stable as nuclear membranes reform during mitosis

Question 6

What are protofilaments?

Answer 6

Microtubules and heterodimers consisting of alpha and beta tubulin
they have positive and negative ends
monomers are added and removed rapidly from both ends
there are 13 parallel protofilaments arranged in a holo tube

Question 7

Functions of Microtubules?

Answer 7

Scaffold for chromatin separation, move cargo to cell locations, support cilia, stabilise cell structure and organise organelle structure

Question 8

Spindle Formation in Chromosome replication?

Answer 8

Spindle consists of microtubules
centrosome contains a pair of centrioles which have stable fused microtubules
the centrosome forms at the two poles of the cell
Kinetochore attaches to the centromere of the chromatid
Aster microtubules attach the centrosome to the cell membrane

Question 9

How to move cargo within a cell?

Answer 9

Two motor proteins with microtubules allow for it
ATP can be hydrolysed allowing it
Kinesin moves forwards and backwards in the cell

Question 10

What are Cilia?

Answer 10

Cilia are membrane bound hair like extensions, microtubules facilitate the movement of components up and down within cilia