mod 7

Question 1

the roles of the cytoskeleton

Answer 1

cell movement
cell division
move membrane bound organelles
move mRNA and cellular components
cell signalling
cell adhesion

Question 2

3 types of cytoskeletal filaments

Answer 2

intermediate filaments
microtubules
actin filaments

Question 3

microtuble monomers

Answer 3

alpha and beta tubulins
both can bind GTP but only beta can hydrolysis w GTP or exchange

Question 4

microfilaments monomers

Answer 4

G actin

Question 5

intermediate filaments

Answer 5

six classes of proteins

Question 6

the microtubule structure

Answer 6

alpha and beta dimers interact and form protofilaments. theres are around 13 side to side. not very flexible. the beta are on the plus end

Question 7

microtubule formation

Answer 7

formation of oligomers (chain of dimers) called nucleation, grows at plus end. need tubilin, GTP and Mg. can treadmill (growth at plus, leaves at minus end). if GPT cap is lost, becomes unstable and collapses

Question 8

MTOC

Answer 8

microtubule organizing centre. the centrosome is an MTOC at interphase and get nucleated at the minus end. there is a gamma-TuRC ring complex around the centrosome

Question 9

what is map and +- TIP

Answer 9

binding protein that increase stability by preventing severing. TIP associates w the plus end

Question 10

what is the barbed end and the pointed end

Answer 10

barbed is the + end and the pointed is the - end.

Question 11

actin formation

Answer 11

occurs near the PM, regulated by external signals, nucleation is regulated by ARF or formins

Question 12

ARF complex

Answer 12

contains 2 actin related proteins, nucleates actin from - end

Question 13

formins

Answer 13

family of dimeric proteins, growing + end, grows straight filaments

Question 14

intermediate filaments

Answer 14

method of IF assembly, dimers are coiled aligned in parallel to for a protofilament tetramer. they also overlap and form the intermediate filament (8 filaments thick)

Question 15

adherens junctions

Answer 15

mediated by cadherin (proteins). it interacts w cytoskeletal elements and associate w actin filaments via p120 alpha and beta catenins

Question 16

desmosomes mediated?

Answer 16

by cadherin, associate w intermediate filaments, give mechanical strength.

Question 17

tight junctions mediated by?

Answer 17

by occludin and claudin interactions. sets up cell polarity as it seals tissue so materials must go thru the cells

Question 18

gap junctions mediated by?

Answer 18

PM is close, consists of clusters of connexins (hydrophillic channels) which creates a pipeline

Question 19

what are the laminin and the basal lamina

Answer 19

provide structural support, an adhesive protein that creates a basement membrane

Question 20

integrins?

Answer 20

bind to components of the extracellular matrix and interact w ECM