Organelles- cytoskeleton Flashcards
what is the cytoskeleton made of
filamentous protein polymers
functions of the cytoskeleton (5)
cell shape, polarity, division, movement and migration, intracellular transport
3 types of cytoskeletons
microtubules, intermediate filaments, microfilaments
what are microtubules made of
polymers of tubulin (alpha/beta tubulin dimers that are stuck together in a string)
how many protofilaments make a microtubule
13
do microtubules have polarity (charged?)
yes
polymerization is what
growing of a microtubule or a microfilament
depolymerization is what
shortening of microtubules and microfilaments
how do they depolymerize
like string cheese, the string of protofilaments peel off
functions of microtubules (3)
cell shape and movement, cell division, providing intracellular organelle movements
what are intermediate filaments made of
polymers of intermediate filament proteins
do intermediate filaments have polarity
no
where can intermediate filaments be found
inside and outside the cells
functions of intermediate filaments (3)
structure, support, adhesion
in what groups can intermediate filaments not be found
plants and fungi
what are microfilaments made of
polymers of actin
how many protofilaments make up a micrfilament
two forming a helix (DNA-esc shape)
do microfilaments have polarity
yes
functions of microfilaments (4)
cell shape and migration, cell division, organelle movement, components of contractile elements of muscle fibers
what does the cytoskeleton help move (4)
the cytoskeleton getting organized to move motor proteins, centrosomes, cilia and flagella
what are motor proteins
proteins that walk across the cytoskeleton carrying vesicles and other organelles
which cytoskeleton form has no motor proteins
intermediate filaments
3 motor families and what they walk on
myosins- microfilaments
kinesins- microtubules
dyneins- microtubules
what are centrosomes
a structure involved in cell division
what do centrosomes do for microtubules
tether them at their bases (neg end)
what makes centosomes
two centrioles surrounded by proteins to help organize microtubules
how do motor families get cilia and flagella to move
dyneins crosslink between microtubules and ‘walk’ causing them to bend the microtubules when active
