University of Illinois Urbana-Champaign MCB 150 FINAL EXAM | Questions with 100% Verified Answers | Latest Update

University of Illinois Urbana-Champaign MCB 150 FINAL
EXAM | Questions with 100% Verified Answers | Latest
Update
Question:
Structure of Microtubules

Answer:
rigid, hollow tubes made of tubulin


Question:
What is tubulin

Answer:
a dimer of alpha-tubulin (GTP) and beta-tubulin (GDP)


Question:
How do tubulin dimers form MTS?

Answer:
they polymerize, assemble mt head to tail so mt has polarity


Question:
Which end do polymerization and depolymerization happen on MT?

Answer:
possible at both ends, but usually occurs at plus end bc minus end is anchored into centrosome


Question:
What happens once there is a dimer addition to a microtubule?

Answer:
GTP in b-tubulin is hydrolyzed and turned into GDP, GTP in a-tubulin is not hydrolyzed for stability


Question:
Dynamic instability and GTP cap

Answer:
GTP bound tubulin prevents subunits from peeling away so if polymerization slows down GTP cap is
hydrolyzed and microtubule starts depolymerizing


Question:
Tubulin + GTP

Answer:

, = polymerization


Question:
Tubulin + no GTP

Answer:
= depolymerization


Question:
Does GTP bound tubulin have high or low affinity for tubulin?

Answer:
high


Question:
Does GDP bound tubulin have high or low affinity for tubulin?

Answer:
low


Question:
Colchicine and Colcemid affect on microtubules

Answer:
Binds tubulin->induces depolymerization->non-specifically affects all microtubules


Question:
Vincristine and vinblastine affect on microtubules

Answer:
Binds tubulin->induces depolymerization->targets rapidly dividing cells


Question:
Taxol affect on microtubules

Answer:
binds microtubules->stabilizes microtubules->targets rapidly dividing cells


Question:
Function of microtubules

Answer:
interphase cell (guiding intracellular transport), dividing cell (segregating chromosomes during
mitosis), ciliated cell (propulsion or sweeping of fluids over membranes)