Cell Cycle (Dr. Pfeffer) Flashcards
What is the basis of cell cycle control?
cyclically activated protein kinases
What is cell cycle control?
a series of counter balances…
- synthesis and degrdation
- phosphorylation and dephosphorylation
Who were the first to characterize cell cycle regulation in different organisms? (this was in red on the ppt…)
Hartwell, Hunt and Nurse (in the ’70s and ’80s)
Microtubule and microfilament disruption will cause the cell cycle to arrest at ___ phase?
M
If DNA replication is disrupted at what phase will the cell cycle arrest?
S
What agents disrupt microtubule function?
vincristine
vinblastine
taxol
colchicine
*arrests cell at M phase
What agents disrupt microfilament structure?
cytochalastin
*arrests cell late in M phase bc this blocks cytokinesis
What is the longest phase of the cell cycle?
G1
What phases of the cell cycle is the chromosome state 4n?
Late S, G2, early M
When will stable cells begin to divide?
When they receive a signal
When will permanent cells begin to divide?
they don’t divide (for the most part)
______ function to ensure correct cycling.
Checkpoints
What is “checked” at the G1 checkpoint?
Is the cell big enough?
Is the enviro right?
Is DNA damaged?
What is “checked” at the G2 checkpoint?
Is all the DNA replicated?
Is the cell big enough?
Describe the Rao and Johnson nuclear fusion experiments? (4 tests)
Nuclei in various phases of the cell cycle we combined to see if the different phases had factors assc with it that influence cells to enter into certain parts of the cell cycle
- S + G1 –> S
(S cell “releases” factors induce G1 to proceed into S) - S + G2 –> nothing
(G2 is resistant to factors from S phase cell) - G1 + G2 –> nothing
(G1 and G2 do not have factors that influence each other) - interphase + M –> M
(M phase has factors that induce all other cells to enter into M phase)
What happens to cells that are not read to transit into the S phase from G1?
go into G0 phase
What happens to cells in G1 that are under stress?
apoptosis
What happens in S phase?
DNA replication and sythsis of DNA pol and histones
What happens in G2 phase?
synthesis of proteins needed for mitosis
What happens in M phase?
mitosis