The Cell Theory
a. All cells come from other cells
b. All living things are made up of at
least one cell.
c. Cells are the basic unit of structure
and function in all living things.
The Cell Cycle
Cell Cycle
• All living things have
a life cycle.
• Individual cells also
have life cycles.
• Cell cycle is a series
of events that takes
place from one cell
division to the next.
Why is cell division important?
• Many-celled organisms (like you) grow
because cell division increases the total
number of cells in an organism.
• One-celled organisms (bacteria, amoeba)
use cell division to reproduce
themselves.
Animated Cycle
http://www.cellsalive.com/cell_cycle.htm
MITOSIS
Mitosis Definition:
The process of cell division that results in
the production of two new daughter cells.
The daughter cells (containing the two
new nuclei) are identical to one another
and to the original parent cell.
Mitosis can be divided into stages
• interphase
• prophase
• metaphase
• anaphase
• telophase
• cytokinesis
mitosis
Interphase
This is not an actual step of mitosis!
the cell prepares for division
• Animal Cell
• DNA replicated
– Organelles replicated
– Cell increases in size
• Plant Cell
– DNA replicated
– Organelles replicated
– Cell increases in size
Interphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase
the cell prepares for nuclear division
• Animal Cell
– Packages DNA into
chromosomes
• Plant cell
– Packages DNA into
chromosomes
Prophase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Metaphase
the cell prepares chromosomes for
division
• Animal Cell
– Chromosomes line
up at the middle of
the cell
– Spindle fibers attach
centrioles to
chromosomes at the
centromere
• Plant Cell
– Chromosomes line
up at the center of
the cell
– Spindle fibers attach
centrioles to
chromosomes at the
centromere
Metaphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Anaphase
the chromosomes divide
• Animal Cell
– Spindle fibers pull
chromosomes apart
– One-half of each
chromosome (called a
chromotid) moves to
each end of the cell
• Plant Cell
– Spindle fibers pull
chromosomes apart
– One-half of each
chromosome (called a
chromotid) moves to
each end of the cell
Anaphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase
new nuclear membranes form
• Animal Cell
– DNA spreads out,
appears as chromatin
(threads)
– 2 nuclei form with
nuclear membrane
– Cell membrane
pinches in to begin
forming the two new
daughter cells
• Plant Cell
– DNA spreads out, appears
as chromatin (threads)
– 2 nuclei form with nuclear
membrane
– New cell wall begins
forming between the
nuclei to begin forming
the two new daughter
cells
Telophase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Cytokinesis
the cytoplasm splits and the cell
divides into two daughter cells
•each daughter cell has its own nucleus
•daughter cells have identical chromosomes
in the nuclei
http://www.bioweb.uncc.edu/biol1110/Stages.htm
Mitosis Animation
http://www.cellsalive.com/mitosis.htm
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Mitosis Animation
http://www.brainpop.com/scie
nce/livingsystems/mitosis/