Gametogenesis
sex cell
beginning
Gametogenesis – gamete formation where
daughter cells, or gametes, are produced at
the end of meiosis II resulting in the
production of sperm and egg.
2 Types of Gamete Formation
Spermatogenesis – the
process of male
gamete production in
animals
Oogenesis – the process of
female gamete production
in animals
Spermatogenesis pictures
Spermatogenesis process
•Spermatogenesis begins with diploid
germ cells called spermatogonia that
grow and develop into a primary
spermatocyte.
•During meiosis I, one
spermatigonium divides into two cells
called secondary spermatocytes.
•Secondary spermatocytes undergo
meiosis II to form spermatids, which
develop into sperm.
•In the end, from 1 parent
spermatigonium 4 sperm cells are
produced.
Spermatogenesis notes
•Spermatogenesis occurs inside
testes
•Within testes spermatogenesis
occurs in walls of seminiferous tubules
•Mature sperm are released into
lumen of seminiferous tubules.
•Spermatigonia & Primary
spermatocytes are 2n
•Secondary spermatocytes are 1n
•Spermatids and sperm are 1n
Oogenesis pictures
Oogenesis process
•Oogenesis begins with a diploid cell called
an oogonium.
•After growth and development, one
oogonium forms one primary oocyte.
•Meiosis I produces a secondary oocyte and
one polar body (due to unequal division of
the cytoplasm).
•Meiosis II in the secondary oocyte produces
an egg and polar body. Meiosis II in first
polar body produces 2 polar bodies.
•The egg survives, while all the polar bodies
die.
•Only one functional egg cell comes from this
process, as the unequal division of the
cytoplasm makes the egg cell big (needs
extra nutrients).
Oogenesis notes
•Oogenesis occurs inside the ovary
•Within testes oogenesis occurs in a
follicle
•Eggs are released into oviduct
•Oogonium & Primary oocytes are 2n
•Secondary oocytes are 1n
•Polar bodies and eggs are 1n
Oogenesis vs. Spermatogenesis
oogenesis
spermatogenesis
Gametes produces
1
4
Location
Ovary
Testes