13. Eukaryotic cell cycle control Flashcards
the cell cycle is unidirectional, what does this mean?
proceeds in a set order - and never reverses
what happens in quiescence (G0)
cells remain dormant for months and even years
what do cell fusion experiments tell us
there must be a mitosis promoting factor in M phase cells
what stage cells respond to mitosis promoting factors
G1, G2, S phase
what stage cells are sensitive to S-phase promoting factor
G1 cells
why are Xenopus and sea urchin embryos frequently studied in cell cycle experiments
high protein content
what are the perks of studying Xenopus
frog cells produce lots of mRNA
what are the perks of studying sea urchins
large eggs that are easy to manipulate
what does MPF stand for
maturation promoting factor
what is the effect of progesterone
induces G2 arrested cells to mature and enter meiosis
what is the effect of adding hydroxyurea to cells in the cell cycle
arrests in S phase as it prevents DNA replication
adding cytoplasm from a cell nucleus arrested in meiosis II achieves what?
what does this show?
same thing as progesterone
- promotes meiosis
there is a soluble factor that can promote meiosis (MPD)
list the order of the cell cycle events
G1 phase
S phase
G2 phase
Mitotic phase
how long do drosophila cell divisions last during embryonic development
8 minutes
what happens once an egg is fertilised
high MPF activity keeps the egg arrested in metaphase of meiosis II
- fertilisation lowers MPF levels and meiosis is completed
