Mitosis/meiosis Flashcards
Name the four parts of the active cell cycles. Which ones comprise interphase?
G1, S, G2, and M; G1, S, and G2
what is the G1 (presynthetic gap) stage?
cells create organelles and increase in size and complement their DNA. must pass restriction site to enter S phase. (must have proper DNA compliment)
what is the S (synthesis) stage?
cell replicates its DNA so each daughter cell will have a copy. cell now has two identical chromatids bound at the centromere. ploidy is still the same: 46 chromosomes. there are now just 92 ‘tids
what is the G2 (postsynaptic gap) stage?
another quality control check point. DNA is replicated, checks to see if enough organelles and cytoplasm for two cells. make sure DNA replication proceeded correctly.
_____ is the main protein associated with regulation of the cell cycle
p53
Prophase
- -condensation of chromatin into chromosomes
- -centriole pairs separate/move to opposite poles
Metaphase
–kinetechore fibers interact with spindle fibers of spindle aparatus to align chromosome at metaphase plate
Anaphase
- -centromeres split so each ‘tid has its own centromere allowing the sister ‘tids to separate.
- -chromatids pulled towards opposite ends of cell by shortening of kinetechore fibers
Telophase
- -spindle apparatus disappears
- -nuc membrane forms around new chromosomes which uncoil
- -cytokenesis
What role do cyclins and CDKs (cyclin dependent kinases) serve?
cyclins bind to CDKs which can then phosphorylate transcription factors, allowing the cell cycle to progress. Cyclin levels fluctuate throughout the cycle.
where are centrioles located and what kind of fibers do they form?
centrosome; spindle fibers (microtubules)
what role do kinetechores serve?
protein on centromere that allows spindle fibers to attach
