G1
the cell grows by producing more proteins and organelles
S
DNA replication occurs
G2
the cell prepares for cell division with the appearance of centrosomes
M
mitosis and cytokinesis occurs
Some cells, like mature nerve cells or muscle cells, do not divide. Other cells will
divide only when the cellular environment signals that it is necessary. What
phase of the cell cycle are these cells said to be in when they are not dividing or
planning to divide?
G0
Name the three checkpoints.
G1 , G2 , M
Indicate the phase of the cell cycle, and what part of the phase (early or later),
where each checkpoint occurs.
G1 - later
G2 - later
M - later
The DNA has been completely replicated and checked for errors.
G2 checkpoint
There is ample supply of energy and raw materials available.
G1 and G2 checkpoint
All chromosomes are attached to the spindles.
M checkpoint
There is adequate room in the environment for more cells.
G1 checkpoint
Which checkpoint appears to regulate whether the cell is in G0 or not?
the G1 checkpoint is the point in the cycle where the cell goes into or out of G0.
Predict the result of a mutation that allows a cell to move past checkpoint G1
even though the cell has not grown sufficiently.
the daughter cell would be small and possibly not able to store enough nutrients within
the cell to survive.
Predict the result of a mutation that allows a cell to move past checkpoint G2
even though the DNA replication has not been completed.
the DNA in the daughter cells would not be complete and the cells would not survive.
Predict the result of a mutation that allows a cell to move past checkpoint M even
though the chromosomes were not prepared for division.
the chromosomes might end up in the wrong daughter cell. for example, one cell might
get both copies of a chromosomes while the other gets none.
Recall that the purpose of the kinases is to phosphorylate other molecules, thus
bringing them to a higher energy state. With this in mind, identify the three parts
of the maturation promoting factor (MPF).