cytoskeleton

Question 1

3 fibers that make up eukaryotic cytoskeleton

Answer 1

microfilaments
intermediate filaments
microtubules

Question 2

microtubules structure

Answer 2

comprised of alpha and beta tubulin dimers
hollow tube shape

Question 3

microtubules function

Answer 3

cell shape movements
movement of chromosomes during cell division
used by cell to move organelles, proteins, viruses
has specialized motor proteins

Question 4

microtubules dynamic instability

Answer 4

constantly switching between growth and shortening at microtubules ends

Question 5

treadmilling microtubules

Answer 5

there are areas that dimmers were more likely to fall off or more likely to join the microtubules at
dimers that fell off came back and joined the microtubule at the end where it was more likely to join back

Question 6

what eukaryotic motility structures do the microtubules comprise

Answer 6

flagella
cilia

Question 7

specialized motor proteins of microtubules

Answer 7

kinesin
dynein

Question 8

kinesin

Answer 8

is the motor protein that moves towards the plus end
end of microtubule where polymerization occurs at a higher rate (more dimers being added than removed)

Question 9

dynein

Answer 9

the motor protein that moves towards the minus end
minus end: end of microtubule where dimers fall off at a higher rate
what allows movement of motor proteins

Question 10

what allows movement of motor proteins

Answer 10

ATP hydrolysis changes the shape of the proteins, allowing them to move along the microtubule

Question 11

how do flagella and cilia differ

Answer 11

in terms of movement and length of the structures
flagella
rotational movement
cilia
whip like motion

Question 12

MTOCs

Answer 12

microtubules are organized in cells by MTOCs
barrel shaped structures made of 9 sets of triplet microtubules
usually found very close to the nucleus
surrounded by an ill-defined pericentriolar matrix

Question 13

microfilaments - composition

Answer 13

comprised out of actin monomers
f actin are actin that are bound to microfilaments
g actin are floating actin

actin bind only when carrying ATP

Question 14

microfilaments function

Answer 14

cell shape
cell movement
plus and minus ends of micro filament depend on rate of addition and falling off of actin
polymerization –> gactin turn into factin
depolymerization –> factin –> gactin

Question 15

treadmilling with microfilaments

Answer 15

governed by ATP hydrolysis
actin with bound ATP join the microfilament
actin with bound ADP fall off

Question 16

motor protein
microfilaments

Answer 16

myosin
use ATP to move in both directions

Question 17

different microfilaments and their role in cell shape

Answer 17

stress fibers: bundles of actin filaments that help maintain skin cell shape and keeps cells elongated

focal adhesions
places where stress fibers attach to the plasma membrane and anchor cells to the substrate or to adjacent cells

microvilli
protrusions filled with stable actin bundles projecting from the cell surface

Question 18

intermediate filaments

Answer 18

many different intermediate filament proteins exist but they all build similar cable like filaments
very stable networks
provide structural support
lamins
not dynamic

Question 19

outside of the plasma membrane
plant cells are encased in

Answer 19

cellulose which acts as a cell wall

primary cell wall and a secondary cell wall laid on when the cell stops expansion

two cell walls stuck together by middle lamella

Question 20

plant cells linked to neighboring cells through

Answer 20

pores that link plasma membranes called plasmodesmata

Question 21

animal cells dont have a cell wall
how does this change things for them

Answer 21

less rigid
anchor themselves to the ECM
matrix of glycoproteins and carb-containing cells

Question 22

what three adhesion molecules do animal cells have

Answer 22

tight junction
sealant on ship

desmosome
less adhesion

gap junction
small protein pores that allow ions sugars and small molecules to pas between cells