Microtubules

Question 1

What MT contain

Answer 1

alpha-tubulin and beta-tubulin

Question 2

MT characteristics

Answer 2

high degree of sequence similarity

found in plant and animal cell

Question 3

alpha tubulin

Answer 3

bound molecule GTP

doesn’t hydrolyse

Question 4

beta tubulin

Answer 4

may have bound GTP/GDP

Question 5

assemble of MT

Answer 5

110kDa heterodimer - polymerising subunit

Question 6

polymerisation of MT

Answer 6

tubular structure with 25nm in diameter and 14nm internal pore

Question 7

formation

Answer 7

starts with nucleating

go in +ve direction

Question 8

polymerisation driven

Answer 8

by GTP hydrolysis

Question 9

depolymerisation driven

Answer 9

by release of tubulin dimers

Question 10

regulation of MT assembly - favourable

Answer 10

polymerisation of free tubulin subunit

Question 11

function of stathmin

Answer 11

binds to 2ab tubulin dimers as it reduces free pool and MT elongation

Question 12

regulation of MT assembly method

Answer 12

• GTP hydrolysis catch up with subunit addition due to loss of GTP cap
• transition from growing and shrinking state
• cause loss of subunit and recycles

Question 13

how contributing to dynamic nature of MT

Answer 13

controlling availability of subunits controls MT elongating or contracting

Question 14

Y-tubulin ring complex matrix

Answer 14

organised by pair of centriole

for microtubule growth

Question 15

stabilisation of MT

Answer 15

create spacing of MT

Question 16

MAP2

Answer 16

defines length between microtubules

Question 17

Tau

Answer 17

2 binding point - A and C terminus

extension not as long as MAP2

Question 18

Intermediate filaments - characteristic

Answer 18

most stable component

least soluble constituent

Question 19

IF made up of

Answer 19

individual monomers coiled up

has helical structure

Question 20

fibrous polypeptide - how assembled

Answer 20

side by side = rise to F with high tensile strength

Question 21

size of fibrous polypeptide

Answer 21

vary from 40kDa to 200kDa

Question 22

different fibrous polypeptide

Answer 22

different cell types between same cell type in different species

Question 23

non-helical region

Answer 23

stabilises filament and interact with other components of cytoplasm

Question 24

IF variable

Answer 24

likely to confer cell type specific function

Question 25

MF and MT feature

Answer 25

have polarity
function may come from different accessory proteins

Question 26

IF and component polypeptide of neurons

Answer 26

neurofilaments

triplet protein 70,140, 210kDa

Question 27

IF and component polypeptide of epithelial

Answer 27

keratin filament
keratin protein
40-65 kDa

Question 28

fibroblasts

Answer 28

vimentin-containing IF

vimentin 55kDa

Question 29

glial

Answer 29

vimentin-containing IF

vimentin and glial fibrillary acidic protein 50kDa

Question 30

muscle - IF component

Answer 30

vimentin-containing IF

vimentin and desmin 51kDa