Lecture 29

Question 1

The cytoskeleton of the cell is

Answer 1

network of protein fibers keeps them suspended in the cytoplasm

Question 2

Functions of the cytoskeleton

Answer 2

1. shape of cell (holding static or changing)
2. position of cellular components
3. intracellular transport and trafficking

Question 3

Three main fiber types of the cytoskeleton

Answer 3

Microtubules
intermediate filaments
actin microfilaments

Question 4

Cytoskeletal fibers are what

Answer 4

protein polymers

Question 5

microtubules are made of

Answer 5

made of alpha and beta tubulin dimers that bind guanosine triphosphate (GTP)

Question 6

microtubules structure

Answer 6

13 protofilaments of dimers forming a hollow tube
+end (beta-tubulin) where MT grows, and -end (alpha-tubulin) where it shortens

Question 7

Microtubule organizing centers

Answer 7

MT organizing centers where the -end is anchored at the end of the +end or growing MT fiber
during mitosis, centrosome organizes these spindle fibers

Question 8

Microtubule functions of cytosolic MTs

Answer 8

1. organize and maintain cell shape and polarity
2. chromosomal movements
3. intracellular transport/trafficking

Question 9

Microtubule functions of axonemal MTs

Answer 9

1. cell motility
2. cilia, flagella

Question 10

Cytosolic MTs are

Answer 10

dynamically growing/shrinking

Question 11

Axonemal MTs are

Answer 11

stable

Question 12

Microfilaments are made of

Answer 12

actin, G-actin

Question 13

G-actin is

Answer 13

globular protein that binds ATP

Question 14

Microfilaments structure

Answer 14

A polypeptide chain of G-actin forms F-actin filament with barbed + end and points - end

Question 15

microfilament functions

Answer 15

1. muscle contraction
2. cell locomotion
3. cytoplasmic streaming
4. cytokinesis
5. maintenance of shape
6. intracellular transport/trafficking

Question 16

Intermediate filaments (IF) functions

Answer 16

provides strength and shape of cell because they are highly insoluble

Question 17

Intermediate filaments are made of

Answer 17

several different proteins like vimentin, keratin, lamin

Question 18

Arrange different cytoskeletal fibers from smallest to largest

Answer 18

1. microfilaments
2. intermediate filaments
3. microtubules

Question 19

Dynamic management of intracellular functions

Answer 19

cytoskeleton supports, organizes and moves components around

Question 20

Kinesins do what for the cell

Answer 20

move cell components along microtubules