In plants, various nonphotochemical quenching (NPQ) processes act as safety valves for photosynthesis that dissipate excess absorbed light energy harmlessly as heat

TLS Online TPP Program

#Id: 7611

#Unit 5. Developmental Biology

Polyspermy occurs more frequently in mouse eggs bearing mutant ZP2 that cannot be cleaved by ovastacin

TLS Online TPP Program

#Id: 7612

#Unit 5. Developmental Biology

A second slow block to polyspermy comes from the so-called zinc spark, the release of billions of zinc ions that is induced by the entry of the first sperm These released zinc ions are bind to the zona pellucida

TLS Online TPP Program

#Id: 7613

#Unit 5. Developmental Biology

Acrosomal enzymes (acrosin and MMP2) as well as the enzymes that help establish capacitation, are inhibited by zinc, the accumulation of zinc on the zona pellucida and in the surrounding cumulus form a “zinc shield” that prevents further sperm entry

TLS Online TPP Program

#Id: 7614

#Unit 5. Developmental Biology

Mechanisms of Egg Activation

TLS Online TPP Program

#Id: 962

#Unit 5. Developmental Biology

Cleavage type- Unequal radial holoblastic cleavage

TLS Online TPP Program

#Id: 963

#Unit 5. Developmental Biology

The point of sperm entry -determines dorsal-ventral axis