15.1-15.7 Flashcards
most cells have what between their S and M phases
gap/growth phases
what happens during G1/G2 phases
growth and ensuring major cell cycle events completed
true or false: CDCs occur continuously
false
how do surroundings influence CDC cycle?
- resource availability for unicellular organisms
- neighbor constraints for multicellular organisms
purpose of checkpoints
- ensure cell cycle event doesn’t start before previous one completed
- dependence of initiation of cycle on cell’s surroundings
what type of organisms are inherently synchronous?
sea urchin, frog, and clam oocytes
how can sea urchin, frog, and clam oocytes be induced to undergo meiotic maturation synchronously
by treatment with appropriate hormones
- go from interphase-arrested state to metaphase-arrested state
are the embryonic divisions after fertilization also synchronous?
the early divisions are, not once you get to blastula
why is size of oocyte amenable for studyign
can be micro-injected with biomolecules
budding yeast
Saccharomyces cerevisiae
fission yeast
Schizosaccharomyces pombe
conditional loss-of-function mutants
grow normally at permissive growth condition and arrest when switched to restrictive growth condition
temperature-sensitive lethal mutations
ex. growth occurs at 25 C and stops at 37 C
what is indicator of CDC stage in S. cerevisiae
bud size
what is indicator of CDC stage in S. pombe
cell length
other experimental organisms besides yeast
- Aspergillus nidulans
- Drosophila melanogaster
- mammalian tissue culture cells
normal primary cells
directly organism, stop dividing after a little bit
cancerous cells
immortalized, can divide indefinitely with the right supplements
hybrid cells (hybridomas)
between normal and cancerous cells - immortalized
fusion of S-phase cell with G1
accelerated G1 phase nucleus into DNA replication
fusion of mitotic cells with interphase cells
chromosomes to prematurely condense
fusion of G2 cell with S-phase cell
S-phase continue to replicate, G2 cell didn’t begin to re-replicate
cyclin-dependent protein kinases
small family of protein kinases which are key components of central cell cycle control system
cyclin-dependent kinase structure
2 polypeptides, CDK subunit binds ATP and contains active site