cell cytoskeleton

Question 1

what is cytoskeleton

Answer 1

network of protein filaments that extends throughout the cytoplasm

Question 2

what is cytoskeleton important in

Answer 2

cell shape, interior organization and movement

Question 3

roles of cytoskeleton?

Answer 3

supports cell
maintains shape
holds cell organelles in position
movements of cytoplasm
interacts with extracellular structures

Question 4

3 types of protein filaments that make up cytoskeleton

Answer 4

microfilament

intermediate filament

microtubule

Question 5

what are microfilaments

Answer 5

polymers of actin proteins (polarized)

Question 6

actin

Answer 6

globular protein (long thing flexible threads)

Question 7

what do actin proteins bind to

Answer 7

to other actin proteins and form helical polymers

Question 8

diameter of microfilament is

Answer 8

7 nm

Question 9

the actin found in microfilaments has __?

Answer 9

distinct ends (plus and minus)

Question 10

what do the distinct ends allow

Answer 10

actin monomers to interact with one another to form long, double-helical chains

Question 11

actin-binding proteins control?

Answer 11

organization of actin filaments

Question 12

microfilaments exist as

Answer 12

• single filaments
• linear bundles
• 2D networks
• 3D gels

Question 13

2 major roles of cortex with microfilaments

Answer 13

determine and stabilize cell shape

help the entire cell or parts of cell move

Question 14

microvilli (supported by microfilaments)

Answer 14

cells that line the intestine are folded into tiny projections

Question 15

microfilaments allow

Answer 15

movement of vesicles inside the cell and cell movement

Question 16

what happens during muscle contraction

Answer 16

actin filaments slide against myosin proteins

Question 17

intermediate filaments (10 nm) are made of

Answer 17

strands of proteins

Question 18

intermediate filaments 4 major classes

Answer 18

1. keratin filaments
2. vimentin
3. neurofilaments
4. nuclear lamins

Question 19

intermediate filaments create

Answer 19

strong durable network in cytoplasm

Question 20

intermediate filaments support

Answer 20

nuclear envelope (strengthens mechanical strength)

Question 21

microtubules are made of

Answer 21

tubular dimers (25 nm)

Question 22

microtubules grow out of

Answer 22

centrosomes

Question 23

dynamic instability

Answer 23

switching back and forth between polymerization and depolymerization

Question 24

Dynamic instability leads to

Answer 24

rapid remodeling of microtubule organization

Question 25

microtubule binding proteins can stabilize

Answer 25

microtubules

Question 26

microtubules roles in cell

Answer 26

form rigid internal skeleton

act as framework for motor proteins moving structures in cell

Question 27

2 types of motor proteins use micritubules

Answer 27

kinesins (+ end)

dyeins (- end)

Question 28

motor proteins use _______ to transport _______

Answer 28

microtubules

organelles
vesicles
macromolecules

Question 29

what distributes the chromosomes in a dividing cell

Answer 29

microtubules

Question 30

what helps position organelles in a eukaryotic cell

Answer 30

microtubules

Question 31

kinesin motor proteins pull the

Answer 31

ER outward along microtubules

Question 32

dynein motor proteins pull the

Answer 32

Golgi apparatus inward along micro to its position near centrosome

Question 33

what allows cilia and flagella movement

Answer 33

microtubules

Question 34

cilia move _______ across cell surface

Answer 34

fluid

Question 35

what are much longer than cilia

Answer 35

flagella propel sperm cells

Question 36

how are cilia and flagella arranged in eukaryotic cells

Answer 36

nine doublet microtubules are arranged in a ring around a pair of single microtubules (“9 + 2” array)

Question 37

the movement of a cilium or a flagellum is produced by

Answer 37

ciliary dynein movement between 2 microtubules