Meiosis
Key Terms
 Diploid: a cell with two of each kind of chromosome,
one from each parent
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Chromosomes of each pair in a diploid are called
HOMOLOGOUS CHROMOSOMES
 Haploid: A cell containing only one of each kind of
chromosome
What is Meiosis?
 Meiosis is the process of cell division that produces
gametes (sperm/eggs) that only contain half the
number of chromosomes from the parent cell
Meiosis Vs Mitosis
 Recall that DNA is replicated during interphase
 Meiosis has the 4 phases of Mitosis, just goes
through them twice
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Prophase 1 and 2
Metaphase 1 and 2
Anaphase 1 and 2
Telophase 1 and 2
All phase 1’s are called meiosis 1, and all phase 2’s are called
meiosis 2
Meiosis 1
Prophase 1
 Homologous chromosomes line up with each other
 Crossing over may occur
 Crossing over is a process where chromosomes actually split
and exchange genetic material
Metaphase 1
 Homologous chromosomes line up at the equator
Anaphase 1
 Homologous chromosomes separate and move in
different directions
Telophase 1
 2 separate cells form, each with only half the DNA of
the parent cell
Meiosis II
 Simple mitotic divisions
Prophase II
 The sister chromatids of the 2 cells formed
previously condense
Metaphase II
 The sister chromatids line up at the equator
Anaphase II
 The sister chromatids separate and move toward
opposite sides of the cell
Telophase II
 The sister chromatids are on opposite sides and 4
new cells (gametes) are produced