Download Mitosis

Mitosis and cellular
division
How do little elephants grow up to be BIG
elephants?
Reproduction is the process by which
organisms produce more of their own kind.

Think about it – Without reproduction,
all life on earth would no longer exist.



Only one parent is involved.
Offspring are genetically identical to
their parents.
All cells that come from a single cell are
genetically identical to it and to each
other; they are all clones.
We have two types of cells in our body
a) Gamete cells – sperm and egg cells
b) Somatic cells – all body cells except
reproductive cells
(examples- skin cells, hair cells,
nerve cells etc)
All somatic cells reproduce by a
process called MITOSIS. This is
ASEXUAL reproduction.
All sexual cells are produced by a
process called MIOSIS. This is
SEXUAL reproduction
The process of asexual
reproduction begins after a
sperm fertilizes an egg.
Skin cancer - the abnormal growth of
skin cells - most often develops on skin
exposed to the sun.
Cell that reproduce by asexual
reproduction reproduce constantly.
We are going to look at how somatic cells
reproduce so that each new cell has the same
complete set of instructions (DNA). That process
is called
Asexual Reproduction
Mitosis
Mitosis is the process in which the
nucleus divides to form two new nuclei.
The two new cells created are
identical.
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A chromosome is
a structure
composed of DNA.

Each chromosome
has a different form.

Humanes have 46
chromosomes in the
form of 23 pairs found
in the nucleus of
each of our cells.

Chromosomes are
particularly visibles
during the division
process of the cell.

Different species
have different
numbers of
chromosomes.
- Humans have 46
- Chicken have 78
- Mosquito have 6
- Rice has 24

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Segments of DNA
determine a
particular hereditary
trait.
A gene is on a
specific spot on each
chromosome.
 We
can divide the life cycle into four
parts:
› 1)
Growth (G1)
› 2)
The synthesis and replication of
chromosomes (S)
› 3)
Preparation for division (G2)
› 4)
Mitosis (M)– cell division
Cell Cycle and Mitosis [3D Animation]
https://www.youtube.com/watch?v=Jc
ZQkmooyPk
Mitosis: The Amazing Cell Process
that Uses Division to Multiply!
https://www.youtube.com/watch?v=g
wcwSZIfKlM
Animated Mitosis Cycle
http://www.cellsalive.com/mitosis.htm
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase & Cytokinesis
Interphase
Prophase
Metaphase
Anaphase
Cell division
Telophase
S
Interphase
G2
G1
M
Chromosomes are copied (# doubles)
• Chromosomes appear as threadlike coils
(chromatin) at the start, but each chromosome
and its copy(sister chromosome) change to sister
chromatids at end of this phase
•
Nucleus
CELL
MEMBRANE
Cytoplasm
Chromatide
Identical
chromatide
Chromosome
Centromere
Two identical
chromosomes
Replication
Anaphase
The centromere is what holds these two identical chromosomes together.
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
chromatin
•
•
•
Mitosis begins (cell begins to divide)
Centrioles (or poles) appear and begin to
move to opposite end of the cell.
Spindle fibers form between the poles.
Centrioles
Sister chromatids
Spindle fibers
Animal Cell
Plant Cell
Spindle fibers
Centrioles
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
Chromatids (or pairs of chromosomes) attach
to the spindle fibers.
Centrioles
Spindle fibers
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
Chromatids (or pairs of chromosomes)
separate and begin to move to opposite
ends of the cell.
Centrioles
Spindle fibers
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
•
•
•
Two new nuclei form.
Chromosomes appear as chromatin (threads
rather than rods).
Nuclear membrane reforms
Mitosis ends.
Nuclei
Chromatin
Nuclei
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
•
Cell membrane moves inward to create two
daughter cells – each with its own nucleus
with identical chromosomes.
Division of the cytoplasm
In plant cells, a cell plate forms across the
centre of the cell, forming a new cell wall
between the two new cells.
Mitosis
Click the picture
above!
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
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http://www.cellsalive.com/mitosis.htm