1. Chapter 7- Fertilization
More historical perspective
Late _____- _______________- sperm are parasites?
Late ______- _____________- Sperm are still parasites?
Early ______- ________- Sperm contribute to fertilization
Late _____- Hertwig and Fol show sperm entering egg, union of _____________ observed

2. Transformation from germ cell to sperm
_________
Derived from centriole
____________
____________
Nucleus is ______
Derived from ______
Mature sperm
Fig. 7.2

3. Sperm __________ ____________ doublet 2 central microtubules Fig. 7.3
A cross-section
A single microtubule
Microtubules are composed of _______
Sperm ___________ provided by______
Dynein is attached to microtubule doublet
Dynein hydrolyzes ___ to bend ________
Human disease- no dynein = _________

4. The egg- loaded with proteins, ribosomes, ______________________________ protective chemicals
(in sea urchin)
______________ (a fibrous mat)- ~8 proteins
Plasma membrane
A ____________ in mammals
Nucleus
_________- a mass of ovarian follicular cells
(in mammals)
Fig Sea urchin egg
Fig Mammal egg

5. 5 steps Egg meets sperm 1. Sperm ______________
Many species use _________________- (migration following a __________________________)
Example- _______ is a 14 AA peptide that attracts sperm in the ___________
Before
After
Point of _____ injection
In mammals, sperm must be ______________prior to fertilization

6. 5 steps Egg meets sperm 2. ______________ reaction
a. Sperm contacts ___________
b. _________________ starts and digests jelly layer
c. Binding to _________ envelope
d. Fusion of acrosomal process with _________________

7. 4 steps
Egg meets sperm
3. Binding to vitelline layer (or _________ ________________)
a. Sea urchin- _________ protein mediates species _____________ and binds to _________ on egg vitelline layer
b. In mice, the protein ____ is the sperm ____________ on zona pellucida
ZP3 also ___________ the acrosomal reaction
A second protein, _____, mediates __________ after the acrosomal reaction

8. 4 steps
Egg meets sperm
4. Fusion of ______ and ________ plasma membranes
Membranes fuse, a ____________________ is formed, and entire sperm enters egg
In mammals, ___________(in the sperm membrane) is essential for ___________
_____________ is bad
Normally, egg and sperm nuclei fuse to create _________ nucleus and single _____________
If two sperm enter-_____________ and messed up division by _________________

9. Egg meets sperm Solutions to __________________
1. ____________- change __________________ of egg membrane
Rapid influx of___________ ions (within 1-3 seconds) post sperm binding
Sperm can no longer ____ with egg membrane
Effect only lasts a _________________
2. ____________- removal of remaining attached _________.
In sea urchin 15,000 _______________ fuse with egg membrane, and clip off ___________, releasing attached sperm
See Sea urchin movie
Cortical granules

10. Egg meets sperm ___________ is key! Sperm Egg Fertilized Egg
What initiates the ____________ reaction??
Sperm
Egg
Fertilized Egg
[Ca++]
___
______
A wave of calcium is released from the _________
________ that is complete in 30 ________
Sperm entry
15sec
30sec
Fig Sea urchin

11. ____ is from mostly from ________ ________ in snails and worms)
Egg meets sperm
What ___________the cortical ___________ reaction??
____ is from mostly from ________ ________ in snails and worms)
If block calcium with a ________ (e.g.EDTA)- block
_________________ reaction
Membrane _______________
Cell __________________

12. Calcium release pathway
Binding receptor activates a _________
____________ which activates ____, which splits PIP2 into DAG and IP3, which activates _____ channel
________________
(PLC)
____+_____
PIP3
Acrosomal process
Plasma membrane
Cytoplasm
Nuclear
membrane
Fig. 7.29B

13. Molecular details of PIP3 signaling
____
____________
Phosphatidyl-inositol 4,5 bisphosphate _____
Inositol 1,4,5 triphosphate _____
Fig. 7.28

14. Nuclear fusion events in sea urchin
When Sperm enters egg-
______________ and __________ disintegrate
______________ partially degrades, and sperm chromatin
______________ (relaxes)
_________extends microtubles in egg and contacts female ____________
Nuclei migrate together and fuse to form ______________
_____ pronucleus
At this stage – we use the terms ________ _________ and _____ ______________.
_______ pronucleus
100
800
Fig. 7.31
Time (secs)