Cytoskeleton

Question 1

Cytoskeleton is important for maintaining?

Answer 1

cell shape, motility, vesicular trafficking, organelle localization, cell signalling and cell division

Question 2

_____is dynamic and this is vital for its function

Answer 2

cytoskeleton

Question 3

What are the three types of cytoskeleton

Answer 3

microtubules
microfiliments
intermediate filaments

Question 4

_____are composed of alpha/beta-tubulin dimers. Each monomer binds to GTP but on____can hydrolysis GTP to GDP. These dimers are held together ___

Answer 4

Microtubles

beta-tubulin

non-covalently

Question 5

___act non-covalently to form protofiliments and these protofilaments associate non-covalent to form either____or____microtubules. There are polar microtubules with a plus end _____and minus end corresponding to the___

Answer 5

tubulin dimers
cytoplasmic or axonemal mircotubles
beta subunit and alpha subunit

Question 6

___ there is net growth at the plus and net loss at the minus end resulting in treadmilling. Tubulins at the minus end are old and are more likely to have ___bound then___. If hydrolysis of GTP to GDP extends all the way from the minus and to plus, the ____called catastrophe

Answer 6

In vitro
GDP rather then GTP
microtubules will collapse in a process called

Question 7

Microtubules formation will often initiate in_____. These contain gamma-tubulin ring complexes that will nucleate formation of the microtubules from the minus end

Answer 7

microtubules organizing center(MTOCs)

Question 8

___is the monomeric subunit that makes up microfilaments. Each monomer binds to ATP but hydrolysis does not play a role in stability

Answer 8

G-actin

Question 9

Mircofilament formation can be initiated by th____which results in branched microfilaments or by____resulting in unbranded mircofilaments. This allows actin to have several distinct properties including filopodia, lemellopodia, pseudopodia and focal stress fibres

Answer 9

ARP 2/3 complex
or formin

Question 10

Signalling pathways that modify the actin cytoskeleton are important___. This involves

Answer 10

for motility in some cells. This involves some of the Rho protein family (monomeric GTPases)

Question 11

____are not polar and are composed of a number of different subunits. Their purpose is to provide mechanical strength to cells

Answer 11

intermediate filaments

Question 12

Adherens junctions and desmosomes require____on adjacent cells to interact. For adherens junstions cadherin is indirectly associated with ___ and form desosomes the cadherin are indirectly associated with ____

Answer 12

cadherins
microfilaments
intermediate filaments

Question 13

For hemidesmosomes and focal adhesions integrins are bound to the___via adhesion proteins such as ___and ___. For local adhesions, integrin is indirectly associated with ____ and for hemidesmosomes integrin is indirectly associated withz______

Answer 13

extracellular matrix
fibronectin and laminin
mircofilaments
intermediate microfilaments

Question 14

Integrins are also____molecules

Answer 14

signalling

Question 15

____form between occluding proteins of adjacent cells , or claudine proteins of adjacent cells. They form a tight seal between cells that does not allow molecules to move between cells

Answer 15

tight junctions

Question 16

_____are formed between connexins on adjacent cells. A small pore forms between adjacent cells allowing free passage of small cytosolic components

Answer 16

gap junctions