Upgrade to remove ads
Only $35.99/year

BIOL172 Final Exam

Terms in this set (97)

What are the steps of fertilization? (3)
1. Sperm penetrate the protective layer around egg.
2. Receptors on the egg surface bind to molecules on the sperm surface.
3. Changes @ the egg surface prevent polyspermy.
What is polyspermy?
The entry of multiple sperm nuclei into egg.
What is an acrosome? & when does an acrosomal reaction occur?
Acrosome- it is at the tip of the sperm that releases hydrolytic enzymes that digest material surrounding the egg.
Acrosomal Rxn- occurs when sperm meets egg.
What is the acrosomal process?
The binding of receptors in the egg in a lock & key fashion.
What is the fast block to polyspermy? & does it occur in mammals?
When gamete & or fusion depolarizes egg membrane & sets up reaction. It does not occur in mammals.
What is the slow block to polyspermy? What element affects slow block to polyspermy?
When a cortical reaction occurs beneath the egg plasma membrane & forms a fertilization envelope. Ca2+ enters the cortical reaction and activates egg to increase respiration & protein synthesis while nuclei of sperm & egg merge.
What is capacitation? & when must it occur?
When mammalian female reproductive tracts alter sperm motility & structure, which must occur before sperm are able to fertilize egg.
What type of block to polyspermy occurs in mammals?
Slow block to polyspermy, which is triggered by the binding of sperm to a receptor in the zona pellucida of egg.
What is cleavage?
A period of rapid cell division w/o growth.
What are blastomeres?
Caused by cleavage in the cytoplasm of 1 large cell into smaller cells.
What are blastula? & Blastocoel?
Blastula- ball of cells w/ fluid filled cavity.
Blastocoel- fluid filled cavity w/ blastula.
What is yolk?
found in frogs & many other animals, which affects the pattern of cleavage.
What is the difference between vegetal pole vs. animal pole? & holoblastic cleavage vs. meroblastic cleavage?
Vegetal pole (more yolk) vs. Animal pole (less yolk)

Holoblastic cleavage= complete division of egg, occurs in spec. w/ less yolk (e.g. sea urchins & frogs).

Meroblastic cleavage = incomplete division of egg, occurs in spec w/ yolk-rich (e.g. reptiles & birds).
What is morphogenesis? And what two processes does it involve?
When cells occupy their appropriate locations. Involves: gastrulation, organogenesis.
What is gastrulation & organogenesis?
Gastrulation= movement of cells from blastula surface to interior of embryo

Organogenesis= formation of organs.
Sets with similar terms