The mammalian egg encounters a heterogeneous population of sperm. Some sperm have undergone the acrosome reaction in or near the cumulus, whereas others have not. The egg have pathways for accepting both types of capacitated sperm.

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#Id: 9047

#Unit 4. Cell Communication and Cell Signaling

Monomeric G proteins are evolutionarily ancient, as evidenced by their widespread functions examples include: 

eIF2

EF1α and EF2

Ran

Sar

Rab

Rho, Rac, and Cdc42

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#Id: 9048

#Unit 4. Cell Communication and Cell Signaling

All G protein–coupled receptors contain seven transmembrane α-helical regions (H1–H7). In many GPCRs a short α helix H8 lies parallel to the membrane surface, and a covalently bound palmitic acid group

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#Unit 4. Cell Communication and Cell Signaling

Three principal classes of G PCR that bind their ligand in different ways:

TLS Online TPP Program

#Id: 9050

#Unit 4. Cell Communication and Cell Signaling

Member of family A of GPCRs -β-adrenergic receptors

Member of family B of GPCRs -glucagon receptor 

Member of family C of GPCRs -glutamate receptor

TLS Online TPP Program

#Id: 9051

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9052

#Unit 4. Cell Communication and Cell Signaling