Mitosis & Meiosis
Cell Life Cycle
Majority of Cell life is in
INTERPHASE
During INTERPHASE
Centrioles replicate
DNA replicates
Cell GROWS
 Mitosis
Mitosis
IN DETAIL
Six steps to Mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
MITOSIS
2N
2N
2N
ALL CELLS AND DNA IDENTICAL
Prophase
The chromatin condenses
into
discrete chromosomes.
The nuclear envelope
breaks down and spindles
form at opposite "poles" of
the cell.
Metaphase
Chromosomes line
up in the middle.
Anaphase
The paired chromosomes
(sister chromatids) move to
opposite ends of the cell.
Once the paired sister
chromatids separate from
one another, each is
considered a "full"
chromosome. They are
referred to as daughter
chromosomes.
Telophase
Nuclei - (plural form of
nucleus) begin to form at
opposite poles.
Nucleoli - (plural form
of nucleolus) also
reappear.
Chromatin fibers of
chromosomes uncoil.
Cytokinesis
Mitosis has ended.
Two new cells are
made.
Mitosis Summary
Mitosis is for the
growth and repair of
body cells.
Remember: Mitosis
makes MY TOE.
2N
2N
2N
Meiosis
Meiosis
2N
Division I
Division II
1N
1N
1N
1N
4 NEW GENETICALLY DIFFERENT CELLS
Meiosis Occurs in two parts!
PART ONE
PART TWO
Prophase I
Prophase II
Metaphase I
Metaphase II
Anaphase I
Telophase I
Anaphase II
Telophase II
Prophase I
Like prophase in
mitosis.
Key Difference:
Crossing Over
Crossing Over
Homologous
Chromosomes – Roughly
same size and have same
genes.
Crossing Over – genes in
the same spot swap with
the other genes on a
chromosome.
Increases Genetic Variety
Metaphase I
Chromosomes line
up in the middle.
Anaphase I
Chromosomes are
pulled apart.
Telophase I
Two Daughter Cells
split.
Each cell has 46
Chromosomes
Meiosis II
Prophase II, Metaphase II,
Anaphase II ,Telophase II
all occur like Mitosis.
Meiosis Summary.
Mitosis
Meiosis
Purpose
Growth,Repair
Sexual
Reproduction
Chromosome #
2N to 2N
2N to 1N
# of cells
produced
# of divisions
2
4
1
2
Genetic
Stays the same
Material
Where it occurs Somatic cells
Variation in
gametes
Gametes