A modification of the agglutination reaction, called agglutination inhibition, provides a highly sensitive assay for small quantities of an antigen. For example, one of the early types of home pregnancy test kits included latex particles coated with human chorionic gonadotropin (HCG) and antibody to HCG. 

TLS Online TPP Program

#Id: 9080

#Unit 4. Cell Communication and Cell Signaling

Binding of acetylcholine triggers the opening of an associated K+ channel  in the plasma membrane via the Gβγ subunit of a Gi protein

TLS Online TPP Program

#Id: 9081

#Unit 4. Cell Communication and Cell Signaling

The increase in K+ permeability hyperpolarizes the membrane, which reduces the frequency of heart muscle contraction.

TLS Online TPP Program

#Id: 9082

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9083

#Unit 4. Cell Communication and Cell Signaling

Cholera toxin, secreted by Vibrio cholerae in the intestine of an infected person, is a heterodimeric protein (AB). 

TLS Online TPP Program

#Id: 9084

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9085

#Unit 4. Cell Communication and Cell Signaling

Subunit B recognizes and binds to specific gangliosides on the surface of intestinal epithelial cells and provides a route for subunit A to enter.