Strength of mortality factors varies with plant productivity, the rate of production of plant biomass. For very simple systems, where few plants exist, not enough plant material is available to support herbivores, and plants must be resource limited, that is, limited by competition.

 

  

TLS Online TPP Program

#Id: 955

#Unit 5. Developmental Biology

Extension of the acrosomal process by the polymerization of G-actin molecules into F-actin by RhoB

TLS Online TPP Program

#Id: 956

#Unit 5. Developmental Biology

Acrosomal process have an insoluble, 30,500-Da protein called bindin.

TLS Online TPP Program

#Id: 957

#Unit 5. Developmental Biology

Species-specific bindin receptors present on the egg vitelline envelope.

TLS Online TPP Program

#Id: 958

#Unit 5. Developmental Biology

Fast block to polyspermy 

Within 1–3 seconds after the binding of the first sperm, the membrane potential shifts from -70mV to about +20 mV

TLS Online TPP Program

#Id: 959

#Unit 5. Developmental Biology

Slow block to polyspermy (cortical granule reaction) becomes active about a minute after the first successful sperm-egg fusion

TLS Online TPP Program

#Id: 960

#Unit 5. Developmental Biology

CGSP, an enzyme that cleaves the proteins linking the vitelline envelope to the cell membrane & also clips off the bindin receptors and any sperm attached to them.