U4M1 pt1 Flashcards
Cell Cycle Regulation
Why do cells divide
Reproduce the organism
- prokaryotes and single cell eukaryotes
Eukaryotic cells also divide to
- replace dead cells
- allow the organism to grow
What phases of the eukaryotic cell cycle
what is the definition of the cell cycle
a period of growth followed by nuclear division and cytokinesis
what is cytokinesis
what is mitosis
the division of replicated DNA equally and precisely
what type of of cell division results in daughter cells that are exact genetic copies
mitosis
what phase of the eukaryotic cell cycle does DNA synthesis occur
S phase
in interphase
when are the centrosomes pulled apart in mitosis
during prophase
What propels the centrosomes apart from one another during prophase
How do the kinetochores of sister chromatids end up facing in opposite directions
What role do non-kinetochore microtubules play during mitosis
During prometaphase, the sister chromatids jerk back and forth. What causes this back and forth motion
How does the size of the daughter cells immediately after cytokinesis compare to the size of the parent cell at the end of G2
Cytokinesis divides the original cell into two daughter cells. How do these daughter cells compare genetically
what phase of the cell cycle do cells spend most of their time
virtually all their time spent Interphase
G1 of interphase
what is interphase
When does interphase begin
as daughter cell from previous division cycle enters initial period of cytoplasmic growth
what are the internal checkpoints of the cell cycle and what do they do
What do cyclins and cyclin dependent kinases control
the internal molecular controls that directly regulate cell division
what is the concentration of cyclins like in the cell
it flucuates cyclically, activating the CDKs appropriately, tells the CDKs what point in the cell cycle the cell is at
what do cyclins and cyclin dependent kinases do
activate/inactivate a large number of proteins associated with cell cycle events
when is cyclin degraded in the cell cycle
the end of mitosis
what is the concentratin of CDKs like in the cell
maintained at a constant level throughout the cell cycle
how much cyclin is in the cell during mitosis
lots, the most it can get
when is cyclin at its highest concentration in the cell
the middle of mitosis
when is cyclin at its lowest concentration in the cell
interphase
how much cyclin is in the cell during interphase
barely any, almost none
at the G1 checkpoint, what happens if it gets the go ahead
the cell cycle will continue and go on the complete division
continue on slide 16
what factors decide whether the cell cycle will continue after the G1 checkpoint
- size
- availability of nutriets
- DNA damage (specifically p53 gene)
at the G1 checkpoint, what happens if it does not get the go ahead
it will likely go into G0, a nondividing state
what’s the deal with the p53 gene
