Meiosis

1
Meiosis
What was our definition for meiosis?

• Definition

Reduction division

• prefix mei means to lessen

• Meiosis Basics

• process used by sexually reproducing organisms to
  form gametes or sex cells

• beginning cell is called a germ cell

What kind of cell did we start with in mitosis?
Somatic diploid cell

• A germ cell is specialized diploid cell

• cell end products are called gametes or sex
  cells

2
Meiosis
GAMETES
Lets talk about sex
cells or gametes
eggs

• female gametes are called ___________

sperm or pollen

• male gametes are called __________________

meiosis
gametogenesis

• formation of gametes is called _________________

oogenesis

• formation of eggs _________________

spermatogenesis

• formation of sperm _________________

• all gametes are haploid cells or n cells

What kind of cells are gametes, haploid or
diploid?
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Meiosis

• Meiosis Basics cont

Germ Cell
Is this cell diploid or haploid?
2n
n
n
Meiosis I
Are these cells diploid or haploid?
n
n
n
n
Meiosis II
4
Meiosis
46
23
23
23
23
23
23
Human Meiosis
5
Meiosis

• Stages of Meiosis

• Let Review, What are the stage of Mitosis?

• Meiosis I

• Meiosis II

Interphase I
Interphase II
Early Prophase I
Early Prophase II
Late Prophase I
Late Prophase II
Metaphase I
IPMATI I
Metaphase II

• Interphase

Anaphase I
Anaphase II

• Early Prophase

Telophase I
IPMATI
Telophase II

• Late Prophase

• Metaphase

IPMATI II

• Anaphase

• Telophase

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Meiosis
Meiosis Overview
7
Meiosis
spermatogenesis
oogenesis
8
Meiosis

• Compare and Contrast Mitosis and Meiosis

Category Mitosis Meiosis
Nickname
starting cell
Starting cell (n or 2n)
cells produced
cells produced (n or 2n)
of cells produced
Names of stages
Normal cell division
Reduction division
somatic
germ
2n
2n
somatic
gametes
n
2n
two
four
IPMATI
IPMATI I IPMATI II
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Meiosis The video
The Circle of Life
23
n
n
23
fertilization
46
2n
zygote
mitosis
2n
2n
meiosis
46
46
n
23
23
n