Cell Division
CELL CYCLE
The cell cycle is divided into 3 main stages:
Interphase, when the cell is carrying out its normal cellular functions
and chromosomes are replicated,
Mitosis when the nuclear division occurs and the cell splits.
Cytokinesis- division of the cytoplasm
3 Stages of Interphase:
The beginning of interphase
The cell grows and develops.
Protein Synthesis and other
cell processes are occuring
The cell is busy being a cell!!
Pull
Pull
Interphase-
*A cell spends 90% of its
life in interphase.
*Chromosomes are
replicated.
* A cell grows to full size.
S
T
f
of
G2 Phase
Pull
Pull
G1 Phase:
Centriole
DNA be
starting
The ce
MITOSIS: Cell division
Results: Mitosis results in 2 identical daughter cells that are
diploid.
Diploid: Cells that have 2 copies of each chromosome or a full
set (2n) of genetic information (DNA).
Somatic (body) cells are diploid.
URPOSE OF MITOSIS:
P
Growth: Mitosis is how your body makes new
cells so you can grow.
URPOSE OF MITOSIS:
P
Repair: Mitosis is how your body
repairs itself.
The roots of your hair are always
growing.
URPOSE OF MITOSIS:
P
Your epidermis is constantly replacing new
skin cells. The life span of skin cells in an
adult is about 50 days.
Maintenance: Replace cells
life.
In 3-4 months your whole blood supply is
completely replaced. A blood cell lasts 60-120
days.
Everyreplaced
day 1% of throughout
your blood cells are
that are
replaced.
While you have been reading this sentence
around 50,000 cells have died and been
replaced.
Other cells are never (or very slowly
replaced, like skeletal muscle cells o
neurons.
The average age of all the cells in an adults body
may turn out to be as young as 7-10 years old.
Intestinal cells are replaced about
every 5 days.
WHAT DOES MITOSIS HAVE TO DO
WITH ME?
1. Mitosis out of control = cancer
2. Mitosis that stops early =advanced aging or disease
such as progeria
3. Many diseases are related to problems with
cell division:
*Cancer
*Alzheimers
*Parkinson's
STAGES OF MITOSIS
2
3
4
5
1. Prophase:
Centrioles
Centrioles move the the sides (poles) of the cell.
Spindle Fibers
Spindle fibers start to form.
Link to
Chromosome
Structure
nuclear membrane
The nuclear membrane dissolves
Chromosome
Chromatin winds up to form
chromosomes.
2. Metaphase:
Spindle Fibers
Line Up
A) Chromosomes line up in the
center of the cell.
B)
ce
3. Anaphase:
Chromosome
Double stranded chromosomes separate.
Spindle fibers anchored to centrioles pull the
chromosomes towards the sides of the cell.
4. Telophase:
Spindle Fibers
B) Spindle fibers dissolve
reform
Interphase
E) The cell will reenter interphase.
Chromatin
C) Chromosomes unwind to
chromatin.
Chromosome
A) Chromosomes continue to moving to the
sides of the cell.
Cytokinesis
Duration of Cell Cycle
On average a cell takes 24 hours to complete
the cell cycle.
Of those 24 hours, approximately 22 hours the cell is in
interphase (G1, S, and G2 Phases).
Then it takes only 2 hours to complete mitosis (prophase telophase).
Put the following
stages of mitosis
in order.