Transcript Spindle fibers

How are elephants able to grow to
such a large size?
The process of mitosis
begins after a sperm
fertilizes an egg.
The Cell Cycle
http://www.cellsalive.com/mitosis.htm
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase
• Cytokinesis
•
G1 (Gap 1) phase – Cells grow to a mature size.
•
S (Synthesis) phase – DNA is copied. The number
of chromosomes double.
•
G2 (Gap 2) phase – Cells prepare for cell division.
Nucleus
CELL
MEMBRANE
Cytoplasm
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
•
•
•
Cell division begins. Chromatin condenses
and changes form into rod shaped
chromosomes.
Centrioles appear and move to opposite
poles.
Spindle fibers form around the centrioles.
The nuclear membrane and the nucleolus
break down.
Centrioles
Sister chromatids
Spindle fibers
• Each chromosome was
duplicated during the
• S phase of interphase.
The two copies are
now joined at the
center. This area is
called the centromere.
• Each half is referred to
as a chromatid. The
two together are sister
chromatids.
Animal Cell
Plant Cell
Spindle fibers
Chromosomes
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
•
•
Sister chromatids attach to the spindle fibers
at the centromere.
Centrioles are attached to the other end of
the spindle fiber.
Sister chromatids move and line up at the
middle or equator of the cell.
Centrioles
Spindle fibers
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
Sister chromatids separate at the centromere
and begin to move to the opposite poles.
Centrioles
Spindle fibers
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
•
•
•
Two distinctive cells begin to form.
Two new nuclei form.
Chromosomes transform back to chromatin
(threads rather than rods).
Mitosis ends.
Nuclei
Chromatin
Nuclei
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
•
•
Cell membrane pinches in to create two
daughter cells – each with its own nucleus
with identical chromosomes.
The pinched area is referred to as the
cleavage furrow in animal cells.
In plant cells, a cell plate forms instead to
form a cell wall and separate the two new
cells.
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
IPMATC
I Play More At The Court