The Cell Cycle and Cell Division Section, study well and solve the assessment at the End of that section.

2. Cell Division
All cells are derived from pre-
existing cells
New cells are produced for
growth and to replace damaged or
old cells
Differs in prokaryotes (bacteria)
and eukaryotes (protists, fungi,
plants, & animals)
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3. Keeping Cells Identical
The instructions for
making cell parts
are encoded in the
DNA, so each new
cell must get a
complete set of the
DNA molecules
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4. DNA Replication
 DNA must be copied or
replicated before cell
division, Original DNA
 DNA is untwisted and strand
separate.
 Every nitrogenous bases
on the strands will pair
up with its suitable base
that floats in the
nucleus.
 Each new cell will then
have an identical copy of
the DNA
Two new, identical DNA strands

5. DNA Shape
Double helix: 2 spirals wound around
each other
But joined in
the middle

6. What’s Happening in Interphase?
What the cell looks like
Animal Cell
What’s occurring
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7. Mitosis
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8. Chromosomes in Dividing Cells
Duplicated
chromosomes are
called chromatids
& are held
together by the
centromere
Called Sister Chromatids

9. Four Mitotic Stages
Prophase
Metaphase
Anaphase
Telophase
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10. Mitosis
• Prophase:
• Chromosomes condense
• Nuclear envelope disappears
• centrosomes move to opposite sides of the cell
• Spindle forms and attaches to centromeres on the chromosomes
• Metaphase
• Chromosomes lined up on equator of spindle
• centrosomes at opposite ends of cell
• Anaphase
• Centromeres divide: each 2-chromatid chromosome becomes two
1-chromatid chromosomes
• Chromosomes pulled to opposite poles by the spindle
• Telophase
• Chromosomes de-condense
• Nuclear envelope reappears
• Cytokinesis: the cytoplasm is divided into 2 cells

11. Cytokinesis
 Means division of the cytoplasm
 Division of cell into two, identical halves
called daughter cells.
 In plant cells, cell plate
forms at the equator to
divide cell.
 In animal cells, cleavage
furrow forms to split cell
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12. Cytokinesis
Cleavage furrow Cell plate in
in animal cell animal cell
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13. Revise and Test Yourself
Review
of
Mitosis
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14. Name the Mitotic Stages:
Interphase
Name this?
Telophase Prophase
Name this?
Metaphase
Anaphase
http://www.cellsalive.com/quiz.htm 14

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