lecture 10and 11

Question 1

______ _______Provide mechanical strength to cells and organelles

Answer 1

intermediate filaments:

Question 2

Intermediate filaments are so named because they are intermediate in size between microtubules and actin filaments

Answer 2

ture

Question 3

Intermediate filaments assemble

Answer 3

Dimers, then tetramers then multimers forming filaments

Question 4

Which type of protein will handle phosphorylation of the nuclear lamins

Answer 4

kinase

Question 5

what are the 3 filament systems

Answer 5

intermediate, microtubles, actin

Question 6

Intermediate filaments act as a ______ or_____to provide mechanical strength to cells and organelles

Answer 6

scaffold or network which are Extensive and very stable assembly interactions

Question 7

keratins provide stength to ___

Answer 7

skin

Question 8

Nuclear lamins provide strength, support

and integrity to

Answer 8

nuclear membrane

Question 9

Nuclear lamins on ____ ____ of the nuclear envelope

Answer 9

the inner face

Question 10

Dynamics of the nuclear lamins are regulated by _____&________through the cell cycle

Answer 10

phosphorylation and dephosphorylation

Question 11

______&________mediated degradation of a subunit of the “cell cycle controller”

Answer 11

Ubiquitin and proteasome

Question 12

All filament systems are _____ that is subunits assemble and disassemble–these processes are further regulated by the cell

Answer 12

dynamic,

Question 13

are intermediate filaments more or less dymaic than All filament systems are dynamic, that is subunits assemble and disassemble–these processes are further regulated by the cell

Answer 13

less

Question 14

microtubules and actin filaments are regulated by similar activities

Answer 14

Nucleotide binding and hydrolysis on growing end of the filament
Proteins acting to influence filaments or monomers

Question 15

actin filaments are bound with

Answer 15

ATP at the end

Question 16

microtubles are bound wiht

Answer 16

GTP at the end

Question 17

Microtubules are composed

Answer 17

of ab-tubulin heterodimer subunits forming protofilaments

Question 18

The “__” ends of microtubules which favor continuing addition of subunits are found at the centrosome.

Answer 18

negative

Question 19

The small, orthogonal or perpendicular structures at the center of the MTOC shown below are termed

Answer 19

centrioles

Question 20

gamma tubulin is located:

Answer 20

at centrosomes

Question 21

Dynamic instability of microtubules refers to the fact that:

Answer 21

Unless capped or stabilized microtubule ends grow rapidly but can and also do suddenly shrink

Question 22

_______ are microtubule motor proteins that use the energy of ______ to move along microtubules

Answer 22

Dyneins : ATP hydrolysis

Question 23

Which of the following is not a function of the microtubule cytoskeleton

Answer 23

Provide mechanical strength to cells in tissues

Question 24

Microtubules - functions(5)

Answer 24

Create polarity in cells
Arrange and move organelles
Tracks for vesicle movement by motor proteins
Cell division
Cell motility

Question 25

Addition of ab heterodimers to growing ends of microtubules depends on

Answer 25

GTP or GDP bound state of tubulins at those ends

Question 26

nucleators are

Answer 26

Proteins acting to influence filaments or monomers

Question 27

Microtubules are organised and regulated much like

Answer 27

actin

Question 28

Microtubule + end growth or shrinkage is

regulated by

Answer 28

GTP binding and hydrolysis

Question 29

In most cell types the plus or growing ends of microtubules are oriented toward the _______and away from the MTOC (microtubule organizing center)

Answer 29

cell periphery

Question 30

Microtubules create

Answer 30

polarity

Question 31

Individual microtubule ends, unless capped or protected are constantly either

Answer 31

growing or shrinking

Question 32

Structure of microtubules

Answer 32

ab tubulin heterodimer,Protofilament

Question 33

In or at which structure does gamma-tubulin act as a nucleator of microtubles in many cell types:

Answer 33

centrosomes

Question 34

Capping proteins can____plus ends from depolymerization to make a stable array of microtubules

Answer 34

stabilize

Question 35

Neurons are a great example of where microtubules function to form tracks for directed transport by ____ motor proteins

Answer 35

vesicle

Question 36

____&____ are microtubule based motors

Answer 36

kinesins and dyneins

Question 37

Motor proteins move cargo on microtubules in a

Answer 37

specific direction towards the + end

Question 38

myosins, the motors of the actin filaments, ____ associate with the filament and light chains control specific cargo binding

Answer 38

heads

Question 39

Microtubules can mediate cell motility via their roles in forming

Answer 39

cilia or flagella

Question 40

Movement is produced by _____ coordinated regulation ofmotors between the outer doublets microtubules

Answer 40

dynein

Question 41

MTOCs of cilia and flagella are ___ ____which are functionally and compositionally related to centrioles.

Answer 41

basal bodies

Question 42

______________&___________is a highly regulated collaboration of DNA and proteins associated with the microtubule cytoskeleton

Answer 42

Cell division and chromosome segregation

Question 43

drug Colchicine

Answer 43

monomer binding

prevents assembly into filament

Question 44

Taxol

Answer 44

filament binding

prevents disassembly