Lecture 18

Question 1

What is the role of the cytoskeleton?

Answer 1

Strength, support, cell shape changed, cell movement, cell contraction, wouldn’t healing, cell interaction.

Question 2

3 types of cytoskeleton filaments

Answer 2

1. Intermediate filaments - Cell strength via keratin and structure via lamins
2. Microtubules
3. Actin microfilaments - regulate cell cortex and cell movement using ATP

Question 3

Explain Intermediate filaments

Answer 3

Contain kertain, vimentin and lamins. Toughest fibres in the body. Tether to other cells via desmosomes. Provide tensile strength

Question 4

How are intermediate filaments made?

Answer 4

8 tetramers twisted into a roselike filament

Question 5

Explain microtubules

Answer 5

Stiff hollow tubes made of tubulin. Anchored at the centrosome. Tubulin is made up of 13 alpha and beta protofilaments to form the microtubule. They grow and shrink independently which is called dynamic instability

Question 6

Where is the starting site for growth of the microtubules?

Answer 6

The nucleation site

Question 7

How does the microtubule shrink and grow?

Answer 7

Tubulin is a G-protein therefore when GTP is blinded they grow and when GTP is hydrolysed to GDP the tubule detached and the microtubule shrinks.

Question 8

Describe actin filaments

Answer 8

Thin fibres involved in cell movement and shape. They are polarised like Microtubules

Question 9

What is the relationship between ATP and ADP?

Answer 9

When ATP is attached to actin it will move in the direction and when ADP is attached it will detach