Biology / Unit 13 Bio 3343 short lesson, about 20 seconds
One Sperm Fertilizes the Egg; Polyspermy Is Actively Blocked
Captions available
The idea
Once one sperm fuses with the egg, per Bio 3341, the egg triggers a rapid membrane change blocking further sperm, preventing polyspermy.
In practice
The fertilizing sperm's entry triggers egg-surface changes that alter the membrane within seconds.
Where people slip
"Fertilization takes many sperm," per Bio 3341, ignores this block keeping fertilization to one sperm.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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