Unit 6

Question 1

Cytoskeleton filaments from smallest to largest

Answer 1

microfilaments, intermediate filaments, microtubules

Question 2

Intermediate filaments are only in ___ cells

Answer 2

Animal

Question 3

Function of intermediate filaments

Answer 3

Function to absorb mechanical strain within cells and tissues

Question 4

Intermediate filaments structure

Answer 4

Long twisting strands on fibrous proteins that form coiled coils

Question 5

IF polarity

Answer 5

Non polar as monomers are orientated in both directions

Question 6

Cytoplasmic branch of IF includes

Answer 6

Keratin filaments, vimentin, neurofilaments

Question 7

Nuclear branch of IF invoudes

Answer 7

Nuclear lamina

Question 8

Actin filaments and microtubules are called polar because

Answer 8

The two ends of the polymer are different from one another

Question 9

Role of desosomes in IF

Answer 9

Join adjacent IF epithelial cells

Question 10

Hemidesomes role in IF

Answer 10

Anchor IFs to basal lamina

Question 11

What subunit is able to hydrolyze GTP to GDP

Answer 11

Beta

Question 12

How would a mutation in IF affect the cells

Answer 12

Restrict its ability to resist tension/ stretching forces

Question 14

Active tubulin is bound to

Answer 14

GTP that readily incorporates into growing plus size end of microtubules

Question 15

Inactive tubulin is bound to

Answer 15

GDP. After being incorporated into microtubule B tubulin hydrolyzes GTP to GDP

Question 16

GTP tubulin has a ___ conformation whereas GDP tubulin is _____ leading to _____

Answer 16

Straight, curved, dynamic instability

Question 17

Rate of polymerization is dependent on

Answer 17

Location

Question 18

What is meant by critical concentration

Answer 18

Min concentration of monomers required for polymer formation to begin, the conc maintained at equilibrium, and conc of monomers where MT switches from shrink to grow

Question 19

What is a MTOC

Answer 19

Sites within a cell where nucleation begins

Question 20

MTOC role

Answer 20

Concentrate y tubulin protein, which is essential for starting microtubule polymerization

Question 21

Examples of MTOC

Answer 21

Centrosome, basal body, spindle pole, plant cell MTOCS

Question 22

How can microtubules be stabilized

Answer 22

MAPS- microtubule associated proteins that organize cytoskeleton and maintain cell shape. Bind different MT together and cap them

Question 23

Dynein and kinesin are both

Answer 23

Motor proteins

Question 24

Kinesin moves towards

Answer 24

Plus end of MT and transports vesicles, organelles, and proteins. Ex. Axonal transport

Question 25

Dynein moves towards

Answer 25

The minus end carrying endosomes, lysosomes, and Golgi derive end vesicles

Question 26

G actin characteristics

Answer 26

Globular form, soluble in cytoplasm, joins together to form, F actin

Question 27

Lamelliopdia

Answer 27

Thin flat projections that extend from leading edge of migrating cells that have a actin rich membrane

Question 28

What controls the behavior of F actin

Answer 28

ABPS - acting binding proteins

Question 29

What does the arp 2/3 complex do

Answer 29

Initiates new actin filaments by creating branches at a 70 degree angle

Question 30

What do integrins do for lamelliopdiums

Answer 30

Helps anchor internal F actin to EC matrix

Question 31

Simple muscle contraction myosin mechanism

Answer 31

ADP bound myosin head is attached to actin, ADP converted to ATP and myosin head slides along filament, power stroke happens as myosin head binds new actin site to og confirmation dragging actin along

Question 32

How does rigor mortis

Answer 32

Occurs when contraction cycle halts and no atp is present to release myosin head, and muscle stays contracted

Question 34

Taxol effect on kinesin on Dynein

Answer 34

Stabilizes microtubule and prevents depolymerization so the mt become overly stable and transport efficiency may decrease

Question 35

Colchione effect on kinesin and Dynein

Answer 35

Destabilizes mt and bind to tubulin to prevent polymerization, so mt don’t have anywhere to move on and transport stops

Question 36

Which end of mt is attached to chromosomes during anaphase

Answer 36

Plus end

Question 37

Structure of anoxemes

Answer 37

9 + 2 arrangement ( ring with 9 pairs and 2 single ones in middle

Question 38

What type of interactions make up actin filaments

Answer 38

Non covalent

Question 39

G actin and f actin interactions

Answer 39

Non covalent