The founder cell (AB) divides equatorially, while the P1 cell divides meridionally (transversely) to produce another founder cell (EMS) and a posterior stem cell (P2).

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#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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#Id: 9049

#Unit 4. Cell Communication and Cell Signaling

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

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#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

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#Id: 9051

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9052

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9053

#Unit 4. Cell Communication and Cell Signaling

Binding of cAMP by an R subunit of PKA occurs in a cooperative fashion; i.e., binding of the first cAMP molecule to CNB-B lowers the Kd for binding of the second cAMP to CNB-A.