Exam 3 Part 1

Question 1

cytoskeleton

Answer 1

structure and movement – the bones and muscles of a cell

Question 2

protein filaments in the cytoskeleton

Answer 2

intermediate filaments
mictrotubules
actin filabments

Question 3

intermediate filaments

Answer 3

middle size ~10 nm 
most variety of filaments
made of lots of different things
NOT dynamic
found throughout cell

Question 4

microtubules

Answer 4

largest filaments
~25 nm
dymanic
a- and b- tubulin
have a growing end and stable end
have an organization center

Question 5

actin filaments

Answer 5

aka microfilaments
smallest filaments ~7 nm
made of actin
dynamic -> cell actively builds and depolymerizes 
can build from both ends
at edges of structures

Question 6

structure of intermediate filaments

Answer 6

ropelike - lots of strength

rebar of the cell

Question 7

cytoplasmic intermediate filaments

Answer 7

keratin filaments (epithelial cells)
vimentin (CT, muscle, glial)
neurofilaments (nerve cells)

Question 8

nuclear intermediate filaments

Answer 8

nuclear lamins in all animal cells (under the membrane, supports the envelope)

Question 9

desmosomes

Answer 9

formed by intermediate filaments “holding” onto other cell’s IF

Question 10

crosslinking proteins

Answer 10

attaches 2 things together like intermediate filaments to plectin

Question 11

intermediate filament association

Answer 11

often associated with other proteins like plectin or microtubules

Question 12

lamins

Answer 12

intermediate filaments in the nuclear lamina

Question 13

nuclear lamina problem

Answer 13

intermediate filaments are not dynamic, so they can’t break down for division
cell phosphorylates them to change shape and then takes it off once division is complete
–uses energy but is quick in both directions

Question 14

progeria

Answer 14

loss of nuclear lamin - causes aging too early due since the structure cannnot handle the stress and does not recover well

Question 15

microtubules

Answer 15

control movement and trafficking
have an organizing center
pull apart chromosomes
made of a and b tubulin

Question 16

centrosome

Answer 16

organizing center for microtubules

Question 17

basal body

Answer 17

centrosomes at cilia - providing the organizing center for microtubules that form the cilia

Question 18

microtubule structure

Answer 18

made up of tubulin heterodimer
hollow
9+0 structure
has a sidedness/polarity

Question 19

9+0 structure

Answer 19

in most microtubules

9 doublets or 18 protofilaments

Question 20

y tubulin

Answer 20

coordinates nucleation

start of microtubule growth - stabilizes microtubules