Home
Flashcards
Preview
7.4 Dynamic Cytoskeleton
Home
Get App
Take Quiz
Create
Does the cytoskeleton move around?
yes, it moves in order to alter the cell's shape, move materials from place to place, and move the entire structure
What are actin filaments (microfilaments)?
smallest diameter
made of actin
How do actin filaments form?
individual actin molecules polymerize and coil around each other
Why do actin filaments have a distinct polarity?
the strand is asymmetrical
the two ends are different and are labeled as plus and minus ends
What is treadmilling?
when filaments grow and shrink as actin subunits are added or removed from each end of the structure
What else does actin filaments interact with during movement?
myosin
What is myosin?
a motor protein that converts ATP into mechanical energy
What makes the head of the myosin molecule bind to the actin and making it move?
the ATP binds to the myosin and then is hydrolyzed into ADP
What is cell crawling?
directional extension of actin filaments pushes the plasma membrane into bulges called "
pseudopodia
" (false-feet)
What is cytokinesis?
cell division in animals
actin filaments are arranged in a circle and must slide past each other, pinching the cell in two
What is cytoplasmic streaming?
directed flow of cytosol and organelles around plant and fungal cells
Intermediate filaments
defined by size
can consist of different proteins
each end is identical
purely structural role
Keratin
makes up the skin
type of intermediate filaments
Nuclear lamins
dense mesh under nuclear envelope
type of intermediate filaments
microtubules
alpha and beta tubulin
largest cytoskeletal components (diameter)
each end of microtubule has different polarity
grow from a microtubule organizing center
help with structure and movement
centrosome
microtubule organizing center in animals
centriole
2 bundles of microtubules within centrosome
not needed for microtubule formation (scientists still not sure why they exist o.O)
function of vesicles
transport material within cells
vesicles travel along ___
microtubule "rail road" tracks
movement continued as long as ATP was available
microtubules necessary for transport
kinesin
motor protein that controls movement of vesicles
similar to a delivery truck that carries transport vesicles along microtubule tracks
"walks" down the microtubule
Bacterial flagella
comprised of protein called flagellin
rotate flagella like propeller
not surrounded by membrane
Eukaryote flagella
comprised of microtubules
whip back and forth
surrounded by plasma membrane
9+2 arrangement
basal body
location where axoneme attaches to cell
important for growth of axoneme
axoneme
9+2 structure of microtubules
isolated structure
Who is Gibbons?
studied cilia
movement doesn't occur unless ATP is available
dynein
a large, motor protein that makes up the arms of the axonemes
when ATP attaches to dynein, the end changes shape and the dynein walks up the microtubule
causes the flagellum to bend back and forth
Author
brendanbui
ID
46833
Card Set
7.4 Dynamic Cytoskeleton
Description
dynamic cytoskeleton section 7.4
Updated
2010-11-03T00:05:14Z
Show Answers
Home
Flashcards
Preview