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)
2
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
3
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
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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