GAMETOGENESIS:
The making of gametes
GAMETE - SEX CELL (SPERM OR EGG)
GENESIS - TO MAKE OR CREATE
Types of Gametogenesis

SPERMATOGENESIS:
Makes MALE sperm cells

OOGENESIS:
Makes the FEMALE egg cells
Both processes use MEIOSIS as their type of
cell division, however the results are quite
different.
SPERMATOGENESIS
Primary
Spermatocyte
46
Where does it occur?
23
In the TESTES
Secondary
Spermatocytes
23
Description of Germ Cells
GERM CELLS in the testes
are DIPLOID (2N, 46) just
like the rest of the body cells.
Initial germ cells are called
PRIMARY
SPERMATOCYTES
What is produced?
1 round of spermatogenesis
produces FOUR healthy sperm
cells. Every sperm cell contains
a unique combination of genes.
(NO TWO ARE ALIKE!)
23
23
23
23
Spermatids
Mature Sperm Cells
OOGENESIS
Primary Oocyte
46
Where does it occur?
In the OVARIES
Secondary Oocytes
Description of the Germ
Cells
GERM CELLS in the ovaries
are DIPLOID (2N, 46) just
like the rest of the body cells.
23
23
23
23
23
X
X
X
Initial germ cells are called
PRIMARY OOCYTES
What is produced?
1 round of Oogenesis
produces ONE healthy egg cell
(OVUM), and THREE POLAR
BODIES. The polar bodies
serve NO PURPOSE in the
body.
3 Polar Bodies
Mature Egg Cell (OVUM)
23
1 Ootid
Once gametes are formed, organisms can
undergo SEXUAL REPRODUCTION
and/or FERTILIZATION.

Sexual Reproduction: The fusion of two gametes

Fertilization: The fusion of the egg and sperm
Critical Concepts/Connections
How is spermatogenesis different from
oogenesis?
 What are three sources of genetic diversity?
(clue: 2 are from meiosis and 1 is from
fertilization)
 How are the terms sexual reproduction and
fertilization different? (Why might scientists
need two different terms)
 In the creation of a child, when is meiosis
necessary and when is mitosis necessary?
