cytoskeleton

Question 1

microfilament capping proteins

Answer 1

CapZ (+ end)

tropomodulin ( - end)

Question 2

microtubule capping proteins

Answer 2

Microtubule associated protein (MAP)

GTP beta tubulin cap

Question 3

microfilament functions

Answer 3

1. organisation and structure e.g. microvilli
2. contractile properties along with myosin II
3. form tracks along which ATP powered myosin V can travel

Question 4

microtubule functions

Answer 4

1. scaffolding
2. tracks for kinesins and dyneins to transport vesciles in both directions
3. spindle fibres
4. length of axons
5. cilia and flagella
6. form lacy network of ER and golgi complex

Question 5

microfilament

Answer 5

G actin + ATP = F actin (polarised)

grows at the + end and disassembles at the - end

Question 6

microtubule

Answer 6

originate from the centrosome
alpha and beta tubulin
beta is always exposed at the + end (growth at this end by heterodimer addition at 3 times the rate of the minus end)
alpha is always exposed at the - end
growth and assembly is dynamic but disassembly is favoured at low temperatures

Question 7

dyneins

Answer 7

will only travel in the + to - direction (retrograde)
functions as a molecule motor to power ciliary and flagellar movements
dynein uses ATP to undergo conformational change which produces a bending motion

Question 8

kinesins

Answer 8

will only travel in the - to + direction
functions with cytoplasmic dynein to move membrane mound organelles through cytoplasm along microtubular tracks
Anterograde fast axonal transport:
kinesin transports NT’s along axon hillock from minus end (centrosome in soma) to + end (at the axon bouton)

Question 9

paclitaxel

Answer 9

anti cancer drug which binds to microtubules stabilising them

Question 10

primary cilia dyskinesia

Answer 10

ectopic pregnancies

Question 11

dynamic instability of microtubules

Answer 11

rapid rounds of growth and shrinkage

Question 12

MAP

Answer 12

microtubule associated protein modulates the stability of the tubules and their capacity to interact with other intercellular compounds

Question 13

nexin

Answer 13

another linkage protein which restricts the extent to which outer tubules can move and prevents dynein from driving the dissolution of the entire complex

Question 14

intermediate filament

Answer 14

very heterogenous and line the nuclear envelope.
provide mechanical support and compressional strength.
do not have intrinsic polarity and they are much more stable then the other cytoskeletal proteins

Question 15

intermediate filament pathologies

Answer 15

Duchennes muscular dystrophy

epidermolysis bullosa