cell cycle Flashcards
Interphase
cell grows and copies its chromosomes; 90% of cell cycle
G1 phase
about 5-6 hours; mRNA and proteins required for DNA synthesis; some organelle replication
S phase
10-12 hours; sister chromatids form but are not visible yet
G2 phase
4-6 hours; final checkpoint before mitosis; some organelle replication
centrosome
spindle microtubules are assembled here for cell cycle
centrioles
pair are found in animal centrosome but are not essential; not in plants
aster
radial array of short microtubules extends from each centrosome
kinetochore microtubules
during prometaphase some spindle microtubules attach to kinetochores of sister chromatids
prophase
first phase of mitosis; sister chromatids are visible
prometaphase
second mitosis stage; nuclear envelope fragments; sister chromatids attach to kinetochore microtubules
metaphase
third mitosis stage; sister chromatids line up at metaphase plate
anaphase
fourth mitosis stage; sister chromatids separate into chromosomes
telophase
fifth mitosis stage; nuclear envelope forms and mitosis is complete
cytokinesis
animal cells-formation of a cleavage furrow; plant cells-formation of cell plate
binary fission
reproduction by prokaryotes (bacteria and archaea)
dinoflagellate mitosis
unicellular protists nuclear envelope remains intact and chromosomes attach to nuclear envelope; microtubules pass through nucleus inside cytoplasmic tunnels
diatoms
unicellular protists also nuclear envelope remains intact; microtubules form a spindle within the nucleus
cyclin dependent kinases
the presence of cyclin and its kinase promotes the passage of different checkpoints
G2 checkpoint
maturation promoting factor (MPF) rises during S and G2 phase and is present to degrade the nuclear lamina in prometaphase
cell division regulators
density dependent inhibition and anchorage dependence
