Cell Division
By: Mr. Kauffman
Outline
• Cells Review
• What is cell
division?
• The Cell Cycle
• Interphase
• Mitosis
• 4 Steps of Mitosis
• Results of Mitosis
•
•
•
•
Meiosis
8 Steps of Meiosis
Results of Meiosis
2 Types of Cell
Division
Cells Review
• Cell: smallest part of any
living thing that carries out
the functions necessary to
support life
• Unicellular organism: living
thing made up of 1 cell
• Multicellular organism: living
thing made up of many cells
What is cell division?
• Cell division: a way to
produce more cells
– Usually 1 cell divides to make 2
cells
• Why is cell division important
to multicellular organisms?
Cancer cell dividing
– Its how they grow
– Replace cells that have died
• Why is cell division important
to unicellular organisms?
– Its how they reproduce
E. Coli cell dividing
The Cell Cycle
• Cell cycle: everything
that happens from 1
cell division to the next
– 2 parts
1. Interphase
2. Mitosis
Interphase
• Interphase: longest
part of the cell cycle
– The cell prepares to
divide
• It grows in size
• It copies its DNA
Mitosis
• Mitosis: Part of the cell
cycle
• Mitosis has 4 steps:
1) Prophase
2) Metaphase
3) Anaphase
4) Telophase
Cell Division
Mitosis Vocabulary
• Diploid = A cell whose chromosomes that appear in
pairs.
• Haploid = A cell that has only one of each type of
chromosome.
• Parent Cell = In cell reproduction name for the original
cell.
• Daughter Cell = In cell reproduction the name for the
cells produced.
4 Steps of Mitosis
1. Prophase
– 1st step
– Chromosomes
form in nucleus
(look like X’s)
•
•
These are how
the DNA is
stored in our
cells
Humans have 46
single
chromosomes (23
pairs)
– Centrioles and
spindle fibers
begin to form
4 Steps of Mitosis
2. Metaphase
– 2nd step
– Spindle fibers
attach to the
chromosomes
– Chromosomes
are lined up in
the middle of the
cell
4 Steps of Mitosis
3. Anaphase
– 3rd step
– Chromosomes
are pulled apart
– ½ of each
chromosome
goes to each end
of the cell
4 Steps of Mitosis
4. Telophase
– 4th step
– Cytoplasm
begins to pinch
in at center of
cell
– Eventually the 1
cell splits to
form 2 cells
– Chromosomes
unravel
Results of Mitosis
• Produces normal, diploid
cells in the human body
– Ex: skin and muscle
• 1 cell splits to form 2 cells
– The new cells are identical
to each other
– The new cells are also
identical to the original cell
Meiosis
• Meiosis is cell division
that produces
reproductive cells
– Ex: sperm and egg cells
• Has 2 cell divisions
– Basically goes through
mitosis 2 times
• Produces 4 cells
– The 4 new cells have ½
the amount of DNA than
the original cell had
2 Types of Cell Division in Humans
Mitosis
Characteristics
Meiosis
Normal body cells
Reproductive cells
4
Types of cells
produced
# of steps
PMAT
Step names
PMAT (1 and 2)
2
# of cells produced
4
46 (single)
# of chromosomes
in cells
Comparison to
original cell
23 (single)
Identical
8
½ the DNA