unit 6 - cytoskeleton

Question 1

cytoskeleton is found in

Answer 1

only eukaryotic cells, almost always animal cells

Question 2

three components of cytoskeleton

Answer 2

actin filaments (diameter ~6 nm), intermediate filaments (diameter ~12 nm), microtubules (diameter ~24 nm)

Question 3

major classes of intermediate filaments

Answer 3

1. keratin filaments in epithelial cells. most abundance type of intermediate filament
2. vimentin and related filaments in connective tissue, muscle cells, and glial cells of nervous system
3. neurofilaments in nerve cells
4. nuclear lamins under the nuclear envelope of all animal cells, provides struture

Question 4

functions of intermediate filaments

Question 5

intermediate filiments composition

Answer 5

rope-like, made of coiled-coiled tetramers
thousands of protein subunits assembled into threads
great tensile strength
abundant in epidermal/skin cells to allow them to stretch without breaking

Question 6

Epidermolysis bullosa

Answer 6

genetic disease of intermediate filaments. mutations in keratin genes. layers of epidermal cells not joined together well, skin is extremely prone to mechanical damage. severe blisters as the skin shears off

Question 7

nuclear lamins

Answer 7

inside
- disassemble via phosphorylation in each cell division, reassemble via in each daughter cell