4 o o o o o o CD 4 Passage VI interphase or mitotic cells Mi

4 o o o o o o CD 4 Passage VI interphase or mitotic cells Microtubules (MTs), which are structural components of cells nuously and shorten. catastrophe stops elongating and starts to shorten. An MT 100 in rescue stops shortening and starts to elongate. When a cell enters mitosis interphase, these transitions con tribute to the rearrange MT the mitotic spindle. Table I shows the values of 3 parameters that were set in 6 computer-simulation models (CSMs A-F) of MT pop- 15 ulations. It also shows the known values of the parameters 10 for interphase cells and mitotic cells. Table 1 235 Catastrophe 80 Cell ty Number frequency Interphase 0.044 Mitotic 2,000 12 6.7 1.9 1.3 1.0 unknown unknown CSMA 500 0.044 CSM B 2.000 0,044 CSM C 0.056 0.044 2.000 0.056 CSM D CSM E 0.019 0.000 CSM F 2,000 0,019 10 t the me in which an MT population is reduced by half \"number of MTs in catastrophe per second number of MTs in rescue per second Figure 1 Table and figure adapted from N. R. Gliksman et a Transition Frequencies of Microtubule Dynamic Instability (Nucl Figure compares, for 3 MT characteristics, the aver- ation, Catastrophe, and Rescue) Regulate Microtubule Dynamics in age values predicted by the with the known average interphase and Analysis Using a Mo Carlo Computer values for the 2 cell types. Simulation.\" 01993 by The American Society for Cell Biology

Solution

Answer:

35. (D) CSM E

CSM E and mitotic cells have equal average MT half-lives of 1.3/min.

36. (G)

From the figure, it is evident that average length of MY during interphase is equivalent to 100 micrometer and that of mitotic phase is less than 20, i.e, 13

37. (A) CSM A

The values corresponding to the 3 parameters are closer in between interphase and CSM A.

38. (G)

39. (B)

Average MT elongation velocity only.

40. (J)

There is a decrease and not increase in the MT average half-life in interphase and mitotic phase.