Unit 2 - Cytoskeleton - Mar 1

Question 1

3 Cytoskeleton Fibers (noncovalent polymers of protein)

Answer 1

large->small
1.Microtubules
2.Intermediate Filaments
3.Microfilaments (aka actin)

Question 2

Microtubules and distribution?

Answer 2

Dynamic/polar
Form structure of cilia/flagella
Walked on by kinesin and dynein motor proteins
Extend from centrosome
Composed of a/b tubulin dimers

Question 3

Intermediate Filaments and distribution?

Answer 3

Symmetrical/nonpolar
Resemble thick twisted rope
Not walked on by motor protein
Stretch across cell, connect cells together
Composed of filamentous subunits

Question 4

Microfilaments and distribution?

Answer 4

Dynamic/polar
Form structural basis of muscle contraction
Walked on by myosin
Most concentrated underneath plasma membrane
Composed of actin monomers

Question 5

Cytoskeletal Motor Proteins

Answer 5

bind and hydrolyze ATP (to ADP), to fuel a conformational rearrangement that causes motor protein to move directionally relative to cytoskeletal fiber (walking proteins)

Question 6

Functions of Actin (Microfilaments)

Answer 6

1.Cell shape and rigidity
2.Mucle contraction
3.Cell Migration (crawling)
4.Cytokinesis

Question 7

Lamellipodia (singular:lamellipodium)

Answer 7

sheet-like structures that push cell forward (cell crawling)

Question 8

Thick Filament

Answer 8

symmetrical, overlapping structure assembled tail to tail by myosin in muscles

Question 9

Sarcomeres

Answer 9

symmetrical structures containing actin (thin) filaments and thick filaments. To contract muscle, sarcomeres shorten in length

Question 10

Dynamic Instability

Answer 10

spontaneous growing and shrinking behavior of microtubule plus ends

Question 11

Key MT (microtubule) functions

Answer 11

1.Spatial distribution of organelles
2.Chromosomal Division
3.Cell cushion

Question 12

Lamin

Answer 12

intermediate filaments that make up nuclear lamina