Please answer the following two questions 16. The exponential assembly phase of
ID: 11290 • Letter: P
Question
Please answer the following two questions16. The exponential assembly phase of an in vitro microtubule assembly reaction consists of rapid tubulin polymerization into polymer. During this phase, the concentration of unassembled tubulin is (greater than/ less than / equivalent to) the critical concentration for microtubule assembly. Due to differences in the conformational changes tubulin undergoes as it assembles at the two ends, the rate of assembly at the plus end will be (greater than / less than / equivalent to) assembly at the minus end.
17. When an in vitro microtubule assembly reaction reaches steady state the concentration of unassembled tubulin will be (greater than / less than / equivalent to) the critical concentration. What general statement can you make regarding the relative rates of assembly and disassembly?
Explanation / Answer
16. The exponential assembly phase of an in vitro microtubule assembly reaction consists of rapid tubulin polymerization into polymer. During this phase, the concentration of unassembled tubulin is (greater than/ less than / equivalent to) the critical concentration for microtubule assembly. Due to differences in the conformational changes tubulin undergoes as it assembles at the two ends, the rate of assembly at the plus end will be (greater than / less than / equivalent to) assembly at the minus end.
17. When an in vitro microtubule assembly reaction reaches steady state the concentration of unassembled tubulin will be (greater than / less than / equivalent to) the critical concentration.
What general statement can you make regarding the relative rates of assembly and disassembly?
critical concentration = when it's assembling
more at positive ends, less at negative ends
when it's at a steady state of concentration, critical concentration for assembly isn't needed - it's already assembled. :)
During in vitro microtubule assembly, tubulin heterodimers join end-to-end to form protofilaments. These associate laterally to form sheets, and eventually microtubules.