The Cell Cycle
Interphase, Mitosis, and Cytokinesis
10-2
Learning Goals
 1. Summarize the cell cycle and what it results in.
 2. Describe the function of the cell cycle in both a
unicellular and multicellular organism.
 3. Define chromosome and describe its parts.
 4. Describe what happens to the chromosomes in
each of the 6 steps of the cell cycle.
Cell Cycle
Cell Cycle - cell division that results in
2 new daughter cells that are an exact
copy of the original (parent) cell.
The Cell Cycle
 Three Main Stages:
 a) Interphase (95%)
 b) Mitosis (5%)
M Phase
 c) Cytokinesis
M phase = cell division
Function
 Unicellular organisms reproduce
this way (asexual reproduction)
 Multicellular organisms make new
cells this way
 Causes organisms to grow
 To replace old worn out cells
 Repair damaged cells
Chromosomes
 Carry genetic information
• DNA = genetic code
Every organism has a different
# of chromosomes

ex: humans have 46 (23 from mom &
23 from dad)

One chromosome = pair of sister chromatids
 Sister Chromatid = 1 copy of wound up DNA
 Sister chromatids are held together by a
centromere
centromere
Sister chromatid
Sister chromatid
Interphase
Prophase
Metaphase
The Cell Cycle
Mitosis
Anaphase
Telophase
Cytokinesis
Interphase
occurs before mitosis begins
Chromosomes,
cytoplasm, and
organelles are
copied.
The cell grows
Mitosis
Prophase
Metaphase
Mitosis
Anaphase
Telophase
Prophase
1st step in Mitosis
The genetic material (DNA)
condenses into bundles called
chromosomes.
Nuclear membrane
disappears
Spindle fibers form
Centrioles move to
opposite sides of the
cell
Metaphase
2nd step in Mitosis
The chromosomes line up along
the middle of the cell

Spindle fibers
attach to the
centromeres of
chromosomes
4.Anaphase
3rd step in Mitosis
Sister chromatids separate and
move to opposite sides of the cell
Telophase
4th step in Mitosis
Nuclear membrane forms around each
set of chromosomes
Chromosomes
unwind into
chromatin
Spindle fibers
disappear
Now you try!
Identify the 4 steps of
mitosis on the next
slide
(Hint: They are not in order)
Telophase
Prophase
Metaphase
Anaphase
Cytokinesis
occurs after mitosis
The cytoplasm
splits in two
Result is two
identical cells that
have the same
number of
chromosomes as
the original cell.
Learning Goals
 1. Summarize the cell cycle and what it results in.
 2. Describe the function of the cell cycle in both a
unicellular and multicellular organism.
 3. Define chromosome and describe its parts.
 4. Describe what happens to the chromosomes in
each of the 6 steps of the cell cycle.