MITOSIS Flashcards
WHAT ARE THE STAGES OF MITOSIS
PROPHASE PROMETAPHASE METAPHASE ANAPHASE TELOPHASE (CYTOKINESIS)
WHAT ARE THE ADVANTAGES OF YEAST AS A MODEL FOR THE CELL CYCLE
- RAPID DIVISION RATE
- CELL CYCLE CONTROL GENES ARE HIGHLY CONSERVED
- CAN BE GROWN AS HAPLOIDS OR DIPLOIDS
- THE CELL CYCLE IS A LOT MORE FLEXIBLE
WHAT ARE THE ADVANTAGES OF XENOPUS AS A MODEL
- EASY TO COLLECT
- LARGE EGGS
- RAPID DIVISION RATE
- SIZE EASIER FOR PROTEIN PURIFICATION
- CAN BE MANIPULATED EASILY
- CAN UNDERGO CELL FREE CELL CYCLE
WHICH CYCLINS DRIVE ENTRY INTO MITOSIS PHASE
B CYCLINS (CDK1)
WHAT HAPPENS IN MITOSIS
- ASSEMBLY OF MITOTIC SPINDLE
- SISTER CHROMATIDS ARE ATTACHED TO OPPOSITE POLES
- CHROMOSOME CONDENSATION
- BREAKDOWN OF NUCLEAR ENVELOPE
- REARRANGEMENT OF ACTIN CYTOSKELETON
HOW DO M CYCLINS DRIVE ENTRY INTO MITOSIS
M CYCLINS INCREASE THROUGH G2 AND M TO CREATE A POOL OF INACTIVE M-CDK COMPLEX. IN LATE G2, CDC25 PHOPHATE IS TRIGGERED TO ACTIVATE THE M-CDK COMPLEX AND SO MITOSIS.
WEE1 - CDK INHIBITORY KINASE
CAK - ACTIVATING KINASE
BALANCE OF THESE HELPS ENTRY
WHAT IS THE ANAPHASE PROMOTING COMPLEX
A PROTEIN THAT IS A UBIQUITIN LIGASE THAT HELPS THE TRANSITION FROM METAPHASE TO ANAPHASE
WHAT ARE THE TARGETS OF THE APC
- SECURIN: IA PROTEIN THAT PROTECTS THE LINKAGES BETWEEN SISTER CHROMATIDS
- S+M CYCLINS: CYCLINS FROM THE PHASES PREVIOUS
THESE MUST BE DEGRADED IN ORDER TO MOVE TO ANAPHASE
HOW CAN YOU GET LOSS OF HETEROZYGOSITY
OR LOSS OF AN ALLELE - HEMIZYGOSITY
- RECOMBINATION
- GENE CONVERSION
- NON DYSJUNCTION
WHAT IS LOH BY NON DYSJUNCTION
FOR SUCCESSFUL MITOSIS TO OCCUR, SISTER CHROMATIDS MUST BE PULLED TO OPPOSITE POLES. IF THIS GOES WRONG, YOU MAY HAVE CHROMOSOMES ENDING UP/OR NOT ENDING UP IN THE CORRECT DAUGHTER CELL.
WHAT IS LOH BY MITOTIC RECOMBINATION
DURING G2 AND M PHASE WHEN EVERYTHING IS CONDENSING, THERE MAY BE SWAPPING OF CHROMATID ARMS.
WHAT IS LOH BY GENE CONVERSION
DNA POLYMERASE BEGINS REPLICATION OF ONE STRAND BY IT MAY ACCIDENTALLY JUMP STRANDS THEREBY, IN THAT PERIOD, COPING ANOTHER STRAND.