Structure of cytoskeleton Flashcards
Cytoskeleton holds…
all organelle structures in place in the cell
Striations in the cytoplasm=
different parts of the cytoskeleton allowing the cell to take up and maintain different shapes
basic structure of a eukaryotic cell
HeLa cells
processes that occur in HeLa cells have more relevance to neuronal function such as…
cytoskeletal function, protein localisation, intracellular transport and vesicle fusion / recycling
cytoskeletal network is made up of…
actin and microtubular networks and intermediate filaments
intermediate filaments
fill the whole cell and give it its shape
actin is found in two forms-
monomeric G-actin and polymeric F-actin (F made in an active process)
Describe actin
thin fibres found throughout cells
how is F-actin formed
G-actin has ATP bound to it and binds to the positive end of the F-actin. The F-actin grows in the positive direction. there are 2 strands which form a double helical filament of F-actin
Where is the actin found
extensively just below the plasma membrane
why is the actin in a double helical structure?
to give it structural strength
what does actin form in muscle fibres?
thin filaments- bind myosin molecules during contraction
describe the structure of microtubules
thick fibres found throughout cells ~20nm in diameter
how are microtubules formed
by polymerisation of alpha and beta tubulin- creates a spiral walled tube
Which direction to microtubules grow
they grow from the positive end but can grow from the -ve end. its an energy bound process but uses GTP instead of ATP.
