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lecture 11

Terms in this set (21)

How do opposing forces pull chromosomes to the metaphase plate
kinetochores pull chromosomes toward the poles and polar ejection force pushes chromosomes towards the equator
there are 13 strands of ____ arranged in a circle around ____
protofilaments, a hollow lumen
each protofilament is made up of ____. Additionally, each protofilament has ____
chains of heterodimers, a plus end and a minus end
what is the subunit of a protofilament
...
β tubulin is the (plus/minus) end that makes up each dimer of ____
plus, a protofilament
α tubulin is the (plus/minus) end that makes up each dimer of ____
minus, a protofilament
each alpha and beta tubular dimer has ____
a bound GTP
what happens when a tubular monomer is added to a polymer
the GTP is hydrolyzed to GDP
the critical concentration is lower at which end
the plus end
the critical concentration of the plus end is (higher/lower) than the critical concentration of the minus end. Why?
lower, you need a lower concentration to add on the plus end than you would need to add on the minus end
n a graph of critical concentration, what happens when the graph hits zero
its at the critical concentration
what happens when the actual concentration is between the critical concentration of T and D. what is this called
monomers are added to the plus end but removed from the minus end. tread milling range
microtubules alternate between slow growth and rapid disassembly which is called
dynamic instability
T/F rescue can occur near the critical concentration
true
what does stathmin do? what is the result?
binds to free tubular subunits, reduces the available free subunit concentration
What is the relationship between stathmin and cancer
cancer cells overexposes stathmin, which leads to cell shape changes associated with malignacy
Why does GTP hydrolysis promote depolymerization
after GTP hydrolysis, filament becomes curved
a microtubule organizing center is called ____. Where is it located?
a centrosome, near the nucleus
What are y tubular ring complexes? where are they located?
they are nucleating sites that surround centrioles and other proteins
microtubules grow outword on the (plus/minus) end from where?
plus, y tubulin ring complexes
what will microtubules do when cut and separated from the centrosome
minus ends point inwards and center around new organizing center that doesn't have centrioles
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