Intermediate Filaments
What are intermediate filaments known for?
Tensile strength
Where do microtubules generally originate in the cell?
Centrosome
What is the name of the microfilament?
Actin
What is the most prominent MTOC within the cell?
Centrosome
What is an example of an intermediate filament?
Keratin
What are microtubules made up of on the most basic level?
Alpha and Beta tubulin dimers
What is the diameter of actin?
7nm
What is the centrosome made up of?
Two centrioles and pericentriolar material
Why are intermediate filaments strong?
How many tubulin dimers make up one microtubule rings?
13
How does actin promote cell motion through pseudopodia in amoeba?
the actin grows from its positive end and shrinks from its negative end causing a treadmilling motion moving the cell membrane outward, then myosin and actin working together contract the cell towards this pseudopod.
What is the structure of the basal body?
It is the same as the centriole with 9 groups of three microtubules in radial symmetry.
What is the name of the basic four unit level of structure?
Tetrad
Which direction do microtubules shrink?
they shrink from the + direction through GDP hydrolysis
How many actin monomers in one microfilament?
2
What is the structure of the axoneme?
Describe the structure of a tetrad?
Two filaments going from the amino group to the carboxyl lying antiparallel to two going the opposite way, formed with alpha helices.
What is the difference between alpha and beta dimers?
alpha(GTP) Beta(GDP) starts as GTP but can be hydrolyzed into GTP on beta
what nucleotide triphosphate is used in actin movement?
ATP
How do the Flagella move?
The Dyenin walks in the negative direction down the microtubules in order to "bend the axoneme" causing the flagella to beat.