Know this information for the AIR test

1. Mitosis Notes

2. Mitosis
 Remember that mitosis is
the name of the cell division
that eukaryotic cells go
through to create a new cell.
 Mitosis is all about the
division of the nucleus and
there are names for each
step that you will need to
learn.

3. Cell Division
Mitosis- process of
making new
somatic (nonsex)
cells like skin cells
(clones)

4. Cell Cycle
 The Cell Cycle –
a repeating set of
events that make
up the life of a
cell.
 Mitosis is actually
a name of one of
the cell cycle
steps usually
referred to as the
M phase.

5. Cell Cycle
 But most people call
the whole process
Mitosis instead of
the cell cycle,
because it is a very
important step.

6. Cell Division
 Where do new cells
come from?
 All cells came from
preexisting cells.

7. Steps of the Cell Cycle
 1. Interphase – the longest phase,
80% of cells life is in this phase.
 Steps of Interphase:
 G1 phase – growth of cell
 G0 phase – inactive stage.
 S phase – DNA is replicated (“S”
synthesis of DNA)
 G2 phase – growth of cell; prepares
for cell division

8. Steps of the Cell Cycle
 G0 phase – non dividing
state after the G1 phase;
 This is the only time a cell can
be stopped from dividing, and
is why a cell spends the
majority of its life in
interphase.
 Some cells in the human body
like spinal cord cells get stuck
in the G0 phase and never
divides again, which is why
spinal cord injuries don’t heal.

10. Cell Cycle
 2. Mitosis – division of the nucleus; a continuous
process divided into 4 phases
 A. Prophase
 B. Metaphase
 C. Anaphase
 D. Telophase

11. M phase
G2 phase
S phase
G1 phase

12. Mitosis
 The following is what
happens during each phase
of mitosis.
 A. Prophase
 Chromosomes appear
 The nucleus begins to break
down
 Centrioles appear and
produce spindle fibers

13. Mitosis
 B. Metaphase
 Chromosomes align
along the equator of the
cell
 Spindles Fibers move
chromosomes to the
equator.
 Spindle Fibers are
attached to the centrioles
(at poles) and connect to
the centromeres on
chromosomes.

14. Mitosis
 C. Anaphase
 Chromosomes are pulled
to the pole by the
contraction of the spindle
fibers
 So, the sister chromatids
are separated at the
centromere

15. Mitosis
 D. Telophase
 The chromosomes begin to form a new nucleus.
 A new cell membrane/wall begins to form so the two cells can
separate
 If there is a cell wall what type of cell are we looking at?

16. Cell Cycle
 3. Cytokinesis – division of the cytoplasm
 The chromosomes start to uncoil and become less dense
 You now have two new genetically identical cells.
 Cytokinesis actually happens during Telophase, so you would
actually say Telophase/Cytokinesis.

17. Telophase/Cytokenisis
 See cleavage in
animal cells
 See Cell plate form
in plant cells.