WebThe ____ _____ is responsible for the slow block to polyspermy through the exocytosis of cortical granules. Cortical reaction The enzymes released by the cortical granules … WebAs we have seen, contact between sea urchin sperm and egg activates the two major blocks to polyspermy: the fast block, initiated by sodium influx into the cell, and the slow block, initiated by the intracellular release of …
Zinc protection of fertilized eggs is an ancient feature of sexual ...
WebSU: first resp in fast-block. Fast block is achieved by changing the electrical potential of the egg cell membrane. This is a transient mech, lasting few secs. Within 1-3 sec of fertilization, resting potential shifts from -70 (low Na+ inside cell vs. high Na+ in the sea water) to +20mv by influx of Na+ ions into cell. WebThe processes by which polyspermy is blocked are of two types: Fast block polyspermy: It takes place by changing the electric potential of the plasma membrane of the egg, the sperm depolarizes the egg membrane. Slow block polyspermy: Certain enzymes like hydrolases, peroxidase, etc. act on the zona pellucida layer and modify the ZP2 and ZP3 ... mug1f2a30dv
Block to Polyspermy I Slow Block I Fast Block I Cortical ... - YouTube
WebPrevention of Polyspermy in Sea Urchin: Fast Block to Polyspermy Fast block is achieved by changing the electrical potential of the egg cell membrane • Within 1-3 sec of fertilization, resting potential shifts from -70 (low Na + inside cell vs. high Na + in the sea water) to +20mv by influx of Na + ions. WebAug 16, 2012 · 8. Prevention of Polyspermy Usually done by preventing multiple sperm from entering the egg Sea Urchins have 2 mechanisms: Fast Block Involves a change in egg cell membrane potential Slow Block … WebThe egg's blocks to polyspermy (fertilization of an egg by more than one sperm) were originally identified in marine and aquatic species with external fertilization, but polyspermy matters in mammalian reproduction too. ... The zona pellucida block to polyspermy has some similarities to the slow block in water-dwelling species, but the ... how to make wine in a crock