BI203 Lecture 23: The Cell Cycle - Stages of Mitosis (Slides 36 - 50) Flashcards
5 phases of Mitosis (prior to cytokinesis):
prophase, prometaphase, metaphase, anaphase, telophase
Prophase:
Chromatin ___
Nuclear envelope ___
Migration of ___
Initiation of ___ ___
condensation, breakdown, centrosomes, mitotic spindle
Sister chromatids attach to each other at the ___.
Spindle fibers attach to chromosomes at the ___.
centromere, kinetochore
The ___ (which duplicated during interphase) separate and move to opposite sides of the nucleus.
They serve as the two poles of the mitotic spindle, which begins to form during late ___.
centrosomes, prophase
___ - transition between prophase and metaphase. Spindle microtubules attach to kinetochores.
The chromosomes shuffle back and forth until they align on the metaphase plate. The cell is then at ___.
Prometaphase, metaphase
Most cells are in metaphase only briefly before proceeding to ___: Links between sister chromatids break; they separate and move to opposite poles of the spindle.
anaphase
___/___ ___ protein kinase (___) is the master regulator of M phase transition.
It activates other mitotic protein kinases and directly phosphorylates structural proteins involved in cellular reorganization.
Cdk1/cyclin B, MPF
Cdk1 activates ___ kinases, which activate ___ kinases, which in turn activate Cdk1.
All of these protein kinases have multiple roles in mitosis.
Aurora, Polo-like
___ maintain linkage between sister chromatids in S and G2.
cohesins
The mechanism of condensation during prophase is not fully understood, but it is driven by ___, “structural maintenance of chromatin” (SMC) proteins.
condensins
Condensins are phosphorylated (activated) by ___/___ ___; they then replace the ___, leaving sister chromatids linked only at the centromere.
Cdk1/cyclin B, cohesins
Breakdown of the nuclear envelope involves changes in all components:
Nuclear ___ fragment
Nuclear ___ ___ dissociate
Nuclear ___ depolymerizes - due to phosphorylation of lamins by ___/___ ___
membranes, pore complexes, lamina, Cdk1/cyclin B
The ___ ___ fragments into vesicles, which are absorbed into the ER or distributed to daughter cells at cytokinesis.
___ ___ breakdown is mediated by phosphorylation of proteins by ___/___ ___ and ___ kinases.
golgi apparatus, Cdk1/cyclin B, Polo-like
Cdk1 and other M phase kinases also lead to:
1) Relocation of ___
(2) Increased ___ turnover
(3) Initiation of ___ ___
centrosomes, microtubule, spindle formation
Microtubule turnover rate increases, resulting in depolymerization and shrinkage of the ___ microtubules.
interphase
