In the dark, most transducin is localized to the outer segment, while most arrestin is found in other parts of the cell; in this condition, vision is most sensitive to very low light levels.

TLS Online TPP Program

#Id: 9090

#XL - T Zoology

This results in continuous activation of the AC of intestinal epithelial cells, chronically active PKA which phosphorylates the CFTR Cl- channel and a Na-H exchanger in the intestinal epithelial cells. 

TLS Online TPP Program

#Id: 9091

#XL - T Zoology

The resultant efflux of NaCl triggers massive water loss through the intestine as cells respond to the ensuing osmotic imbalance causes severe dehydration and electrolyte loss.

TLS Online TPP Program

#Id: 9092

#XL - T Zoology

Pertussis toxin, produced by Bordetella pertussis, catalyzes ADP-ribosylation of the  subunit of Gαi, preventing GDP-GTP exchange and blocking inhibition of adenylyl cyclase.

TLS Online TPP Program

#Id: 9093

#XL - T Zoology

Ligand binding to GPCRs that activate Gαq, leading to activation of phospholipase C

TLS Online TPP Program

#Id: 9094

#XL - T Zoology

Phospholipase C cleaves a phospholipid known as PI(4,5) P2, generating two second messengers: 

diffusible IP3 and membrane-bound DAG

TLS Online TPP Program

#Id: 9095

#XL - T Zoology