01-15.03
Animal Development I
Where it all begins…
Animal Development I
 When

does development begin?
Where is the beginning of a circle!?*
 Where
 What
should we start?
is gametogenesis?
Where do sperm come from?
 Where do eggs come from

Some Gamete questions…
 Why
are gametes required for sexual
reproduction?
 What
makes gametes different from
somatic cells?
What is ploidy?
 Remember meiosis

Fig 12.5
Some Gamete questions…
 How
have gametes become
specialized?

Hint: think morphology…
More about gametes
 Where
do sperm come from?
Why do mammals have testes?
 What is the structure of testes? (fig
59.11, 13)
 What are germ cells?
 What are stem cells?


How many sperm form from each germ
stem cell?
More about
spermatogenesis
 What
is the progression from germ
stem cell to sperm?
What is a germinal cell (aka germ cell
stem cell)
 What is a primary spermatocyte
 What is a secondary spermatocyte
 What are spermatids?
 What are spermatozoa?
 What do sertoli cells do?

More about gametes…
 What

What is their major cargo?


about eggs?
Nutrients, cytoplasmic determinants,
maternal chromosomes
How do they protect themselves?

What sort of structural adaptations do they
display?



What is a jelly coat?
What is a vitelline membrane?
What is a zona pelucida?
More about eggs
 How
valuable are they?
How many are made?
 When are they made available?

 How
do they find the sperm?
Who finds whom?
 Are eggs motile?

More about eggs…
 What
are cytoplasmic determinants?
mRNA, protein, other molecules
 Where are they located?
 When are they depositied?



How are they distributed?


What is oogenesis?
What happens during cell division?
What do they do?

What is polarity?
Fig 17.14
More about eggs
 Where
do eggs come from?
Why ovaries?
 What is the structure of ovaries? (fig
59.16)

More about eggs
 Where
do eggs come from?
What cellular process is involved?
Meiosis again…
 How many eggs form from each germ
stem cell?

More about eggs
 How
does egg structure differ
between organisms?
Jelly coat (sea urchin) vs. zona
pellucida (mammal)
 No cell layer (sea urchin) vs. granulosa
(mammal)
 Yolk differences


More later…
Back to fertilization
 What
are model organisms?
 What
are the models for studying
fertilization?
 The
rules of engagement…(fig 60.3)
What does the sperm encounter first?
 How can it get through the jelly coat?

More about fertilization
 What
is penetration (aka. the
acrosome reaction)? (fig 60.3)

Remember the acrosome?


Remember the jelly coat/zona pellucida?
What happens when the acrosome
encounters jelly coat?
What are the signals?
 What are hydrolytic enzymes?
 What do they do?

More about fertilization
 More

How does the sperm penetrate jelly
coat?


What is the acrosomal process
What happens at the vitelline
membrane?


acrosomal reaction…
Why are receptors important?
What happens next?
Sperm and egg membranes fuse
 HOORAY!!!

More about fertilization
 What
is the situation?
How many eggs are available?
 How many sperm are available?
 Only ONE winner!

 What
is polyspermy?
 How is polyspermy prevented?
Fast block to polyspermy
 Slow block to polyspermy

The fast block to
polyspermy
 What
is membrane potential?
 What happens to the membrane
potential upon sperm fusion?
 How does depolarization prevent
polyspermy?
 How long does the fast block to
poplyspermy last?
The slow block to
polyspermy
 How

does the slow block work?
What is signal transduction?
What are second messengers?
 Why do we need them?

More about the slow block
 Where
are intracellular Calcium
stores?
How is calcium release triggered?
 How does it radiate over surface of
egg?


Doing the Calcium wave…

http://sdb.bio.purdue.edu/dbcinema/
Campbell fig 47.3
More about the slow block
 What
does calcium release do?
Cortical granules fuse with PM
 Release contents into perivitelline
space

 What
are cortical granules?
Where are they located?
 What do they contain?

enzymes
 mucopolysacchariddes

More about the slow block
 What
do mucopolysaccharides do in
perivitelline space?
Remember osmosis?
 How do mucopolysaccharides affect
osmolarity?
 What does this do to perivitelline
space?

More about the slow block
 What
do the enzymes from cortical
granules do?
What happens when polysaccharides
become crosslinked?
 How would this affect sperm
penetration?

 How
long does all of this take?
What have we learned?
 Preformation
vs. Epigenesis
 Fertilization
Acrosome reaction
 Fast block to polyspermy
 Slow block to polyspermy (aka cortical
reaction)

Next day
 Cleavage
and Morphogenesis