Brazeau - Mitosis Flashcards
Prophase
Chromosomes condense, initial formation of spindles, nuclear envelope breaks down
Metaphase
Spindle microtubules attach to kinetochore, chromosomes align at center of spindles
Anaphase
Sister chromatids separate and move to poles
Telophase
Reformation of nucelar envelope, chromosome decondensation
Checkpoint that must be passed to enter mitosis?
G2 Checkpoint
- DNA Completely synthesized
- No DNA Damage
CDK1/Cyc B
What regulates transition from G2 to M phase?
MPF
CDK1 and Cyclin B
What is the role of MPF?
Once activated, phosphorylates downstream targets responsible for mitosis in positive feedback loop with Aurora Kinase/Polo-like Kinase
- Chromatin Condensation
- Nuclear Envelope Breakdown
- Fragmentation of Golgi
- Spindle formation
What is popular target for cancer drugs in the cell cycle?
Spindle formation in prophase
During DNA replication (S phase), what binds sister chromatids along full length?
(e.g. what maintains linkage of newly synthesized sister chromatids)
Cohesins
What does condensin require to promote condensation of chromatin?
ATP
What drives the shift from cohesin to condensin?
Cyc B, CDK 1, PLKinas
In what phases do each chromosome consist of two sister chromatids until separation at anaphase?
G2 and M
During G2 what holds sister chromatids together along their length?
What occurs during prophase?
Cohesin
Cohesin is removed from most of the length–but stays at the centromere; at the same time condensin begins to condense chromosomes
When are the chromosomes completely condensed?
Metaphase
What initiates nuclear envelope breakdown?
Lamins depolymerize when phosphorylated by MPF (CycB/CDK1)