Transcript 1.3a-Mitosis

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Cell Cycle…
• Does your cell cycle look something like this?
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Lesson #1.3a
- Mitosis
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Identical Daughter Cells
Two
identical
daughter
cells
Parent Cell
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Chromosomes
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Chromosomes in Dividing Cells
Duplicated
chromosomes are
called sister
chromatids &
are held
together by the
centromere
Called Sister Chromatids
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Karyotype
A picture of the
chromosomes from
a human cell
arranged in pairs by
size
First 22 pairs are
called autosomes
Last pair are the
sex chromosomes
XX female or XY
male
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Boy or Girl?
The Y Chromosome Decides
Y - Chromosome
X - Chromosome
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Cell Reproduction
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Types of Cell Reproduction
Asexual reproduction involves a
single cell dividing to make 2 new,
identical cells, these are called
daughter cells
Mitosis & binary fission are examples of
asexual reproduction
Sexual reproduction involves two
cells (egg & sperm) joining to make a
new cell (zygote) that is NOT
identical to the original cells
Meiosis is an example
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Cell Cycle
DNA Copied
Cells
Mature
Daughter
Cells
Cells prepare for
Division
Cell Divides into
Identical cells
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What’s Happening in Interphase?
What the cell looks like
Animal Cell
What’s occurring
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Mitosis
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Mitosis
Division of the
nucleus
Only occurs in
eukaryotes
Produces somatic
cells (ALL but
sex cells)
Has four stages
Doesn’t occur in
some cells such
as brain cells
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Four Mitotic Stages
Prophase
Metaphase
Anaphase
Telophase
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Early Prophase
Chromatin in nucleus continues
condensing
Mitotic spindle forms from centrioles
Microtubules make up the spindle fibres
Nucleolus
Cytoplasm
Nuclear Membrane
Chromosomes
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Late Prophase
Nuclear membrane & nucleolus are
broken down
Chromosomes continue condensing &
are clearly visible
Spindle fibers attach to the
centromere of each chromosome
Spindle begin to move to the
opposite ends of the cell, stretching
out the cell
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Late Prophase
Chromosomes
Nucleus & Nucleolus have disintegrated
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Review of Prophase
What the cell
looks like
Centromeres
What’s happening
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Metaphase
Chromosomes, attached to the
centromeres and move to the center of
the cell
Chromosomes are now lined up in the
middle
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Metaphase
Spindle
Fibers
Chromosomes
lined up in
the middle
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Metaphase
Chromosomes
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Review of Metaphase
What the cell looks
like
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Anaphase
Occurs rapidly
Sister
chromatids are
pulled apart to
opposite poles
of the cell by
spindle fibers
Cell elongates
(gets wider)
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Anaphase
Sister
Chromatids
being
separated
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Anaphase Review
What the
cell looks
like
What’s
occurring
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Telophase
Sister chromatids are now at
opposite poles
Spindle disassembles
Nuclear envelope forms around
each set of sister chromatids
Nucleolus reappears
CYTOKINESIS begins at the end
of this stage
Chromosomes reappear as
chromatin
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Comparison of Anaphase & Telophase
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“Activity: Mitosis
Practice” worksheet
(front side only)
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Cytokinesis
Means division of the cytoplasm
Division of cell into two,
identical halves called daughter
cells
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Mitotic Stages
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Daughter Cells of Mitosis
Have the same number of
chromosomes as each other and as
the parent cell from which they
were formed
Identical to each other, but smaller
than parent cell
Must grow in size to become mature
cells (G1 of Interphase)
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Identical Daughter Cells
Chromosome number the same
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Review
of
Mitosis
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Name the Mitotic Stages:
Interphase
Telophase
start
Prophase
Metaphase
Anaphase
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Eukaryotic Cell Division
 Used for growth and
repair
 Produce two new cells
identical to the original
cell
 Cells are diploid (2n)
Prophase
Metaphase
Chromosomes during
Metaphase of mitosis
Anaphase Telophase Cytokinesis
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REMEMBER…
 PMAT + Cytokinesis = Mitotic Phase
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Mitosis Animation
Name each stage as you see it occur?
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Mitosis in Onion Root Tips
Do you see any stages of mitosis?
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Test Yourself
over Mitosis
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Name the Stages of Mitosis:
Anaphase
prophase
Metaphase
Interphase
Prophase
cytokinesis
Telophase,
Prophase
Anaphase
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Identify the Stages
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Prophase
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Metaphase
Prophase
Anaphase
Anaphase
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Telophase
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Telophase
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1. “Activity: Mitosis Practice”
worksheet (back side)
2. CELL CYCLE worksheet and questions
3. Mitosis Worksheet #1-24 & #1-10
4. Mitosis QUIZ practice
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