BIOGEOGRAPHIC CLASSIFICATION OF INDIA

Our country can be conveniently divided into ten major regions, based on the geography, climate and pattern of vegetation seen and the communities of mammals, birds, reptiles, amphibia, insects and other invertebrates that live in them.

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SAP in the egg jelly of the sea urchin Arbacia punctulata 

Resact (14-amino acid chemotactic peptide)

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SAP in the egg jelly of, Strongylocentrotus purpuratus

Speract

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Resact from Arbacia egg jelly binds to its receptor on the sperm, activates the receptor’s guanylyl cyclase (RGC) activity.

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Active guanylyl cyclase causes the sperm cell to produce more cGMP, that activates a calcium channel in the cell membrane of the sperm tail.

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Sperm-specific calcium channels are encoded by CatSper genes

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Increase in cGMP and Ca2+ activate both mitochondrial ATP-generating apparatus and the dynein ATPase that stimulates flagellar movement in the sperm.