substance that prevents cells from synthesizing spindle fibres. How would this substance affect cell division?

Why does catastrophe (the rate at which growing microtubules switch to a Contracting State) cause a decrease in the number and length of microtubules?

Which statement is likely true given the infomation in the diagram? Net1 Cdc20 APC АРС Cdc5/Polo Cdc14 -- Cdc20 APC АРС Hct1 Hct1 Lag Mad2 Cdc20 Hct1 Cdc14 APC APC Incomplete spindle Sict Sic1 В Cdk1-cyclin Anaphase inhibitors Mitotic cyclins S/G2 Metaphase Anaphase Spindle disassembly Cytokinesis DNA re-replication O Cdc5/Polo is a phosphatase. O An overactive, gain of function mutation in Mad2 would cause metaphase arrest. O A overactive, gain of function mutation in Cdc14 would cause prolonged metaphase or metaphase arrest. O The outcome of Cdh1/Hct1 activity is a rapid rise in MPF/M-CdkC activity. H-1

In a dividing cell, the duplicated sets of chromosomes move along microtubules to opposite ends of the cell. How would you use an inhibitor to show that microtubules are essential for chromosome separation?  What control treatment(s) would you use? What kind of cell junctions would you expect to find, and why, in a small animal where a chemical signal passes rapidly through cells to go from the head to the tail?

Scientists in the lab have isolated a substance that prevents cells from synthesizing spindle fibres. What is this substance and how would this substance affect cell division?

Oncologists (cancer doctors) frequently measure the mitotic index of tumor cells when they are removed via surgery or biopsy.  What do you think is the value of finding out the mitotic index of these cells?