Chapter 7- Fertilization in Mammals
*Factors responsible for initiating the cortical granule reaction:
Ca++ PLC and IP3-Provide experimental evidence to support your answer.
Why is sperm and egg recognition in mammals less important than in sea urchins?
Internal Fertilization
Role of the female oviduct in sperm translocation:
Muscular contraction and cilia beating
Major differences in mechanisms involved in preventing polspermy between sea urchins and mammals?
No fast block in mammals, and cortical granule reaction does not result in a fertilization envelope
The process of egg activation in mammals is similar to what?
That in sea urchins
Capacitation defined:
The process by which the sperm become competent to fertilize the egg. The process involves physiological changes resulting from interactions between the sperm and female reproductive duct.
The molecule located on the mouse zona that mediates sperm and egg binding:
ZP2
*2 mechanisms by which gametes from the sea urchin species recognize each other:
chemotaxis—resact, close protein interactions—egg jelly factors, bindin and its receptors
*Polyspermy-
entry of more than one sperm into an egg
* What mechanisms are evolved to prevent polyspermy in sea urchin?
fast block—change in membrane potential, and slow block—cortical granule reaction
*What is acrosomal reaction:
fusion of acrosomal and sperm membranes—exocytosis of proteolytical enzymes, and generation of acrosomal process in sea urchin
2 major differences in the fusion of genetic materials between sea urchin and mammals?
much longer in mammals, no true diploid zygote nucleus till after the first cell division
*Major events in fertilization:
sperm and egg recognition, regulation of sperm entry, fusion of genetic material (considered last stage), activation of egg metabolism
Fertilization:
the process whereby two sex cells (gametes) fuse to together to create a new individual with genetic potentials derived from both parents
*Accomplishment of fertilization:
transmission of parental genes to offspring, and initiation of developmental processes
