What controls mitosis Flashcards
The cell cycle or cell-division cycle is the series of events that take place
place in a cell leading to its division and duplication of its DNA replication) to produce two daughter cells
The cell cycle consists of____distinct phases
4
G1 phase
S phase Interphase
G2 phase
mitosis
Interphase
G1 phase
S phase
G2 phase
Cells that have temporarily or reversibly stopped dividing are said to have
entered a state of quiescence called
G0 phase
Exam the diagram to the right, predict which phase(s) of the cell cycle is
the shortest
Mitosis and cytokinesis
. For a
typical rapidly proliferating human cell with
a total cycle time of 24 hours
the G1 phase might last about 11 hours,
S phase about 8 hours,
G2
about 4 hours, and
M about 1 hour
A checkpoint is one of several points in the eukaryotic cell cycle at
which the progression of a cell to the next stage in the cycle can be
halted until conditions are favorable
Damage to DNA and other external factors are evaluated at the
G1
checkpoint
if conditions are inadequate, the cell will not be allowed to
continue to the S phase of interphase
The G2 checkpoint ensures all of the
chromosomes have been replicated and
that the replicated DNA is not damaged before cell enters mitosis
The M checkpoint determines whether all the
sister chromatids are correctly
attached to the spindle microtubules before the cell enters the irreversible
anaphase stage
Two groups of proteins responsible for promoting the cell cycle
, cyclins and cyclin-dependent kinases (Cdks),
Cyclins regulate the cell cycle only when they are
bound to Cdks;
; to be
fully active, the Cdk/cyclin complex
must be phosphorylated, which
allows it to phosphorylate other proteins that advance the cell cycle.
cyclins and cyclin-dependent kinases
are positive modulators
