exam 5 extra

Question 1

What are 5 functions of the cytoskeleton?

Answer 1

1. determines cell shape
2. organizes organelles and interior components
3. coordinates movement of molecules in the cell
4. facilitates movement of the cell
5. provides structural support

Question 2

What are the 3 types of filaments?

Answer 2

intermediate filaments, microtubules, and actin filaments

Question 3

How is an intermediate filament formed?

Answer 3

1. IF protein monomer contains a central rod domain and uns
   structural domains on either end
2. two monomer wrap around each other in a coiled formation, making a dimer
3. two dimers associate with each other in a staggered manner to form a tetramer
4. the dimers will move in opposite direction
5. the tetramers line up end to end to form one strand
6. 8 of these strands line up and twist in a rope like structure that can be added in units to the end of a growing filament

Question 4

what are two classes of motor proteins?

Answer 4

dynein and kinesin

Question 5

when actin filaments nucleate, what does the rate of polymerization depend on?

Answer 5

depends on the actin concentration

Question 6

what is cell crawling controlled by and what are the 3 steps?

Answer 6

controlled by actin, and is where cells like amoeba and neutrophils find food and prey by crawling along a surface
-3 steps;
1. cell pushes out protrusions at the ‘leading’ edge
2. protrusions adhere to surface, using protein complexes to help attach
3. the cell drags itself forward using the adhesion complexes to anchor the cell

Question 7

what 3 things must cells accomplish to reproduce?

Answer 7

1. duplicate the contents (DNA, organelles)
2. separate the material into the two daughter cells
3. coordinate the timing of these steps