Leaky Expression

In repressed state, an occasional transcript gets made. This happens because every so often, RNA polymerase will manage to bind the promoter in place of the Lac repressor. This leakiness encode meager level of Z, Y and A.

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#Id: 954

#Unit 5. Developmental Biology

When sulfated polysaccharide binds to its receptor on the sperm, activates 3 sperm membrane proteins: 

(1) A calcium transport channel

(2) A sodium-hydrogen exchanger

(3) A phospholipase enzyme (IP3)

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#Id: 955

#Unit 5. Developmental Biology

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

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#Id: 956

#Unit 5. Developmental Biology

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

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#Id: 957

#Unit 5. Developmental Biology

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

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#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

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#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