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Membrane-Bound Receptors, G Proteins, and Ca2+ Channels (Quiz 2)

View the animation below, then complete the quiz to test your knowledge of the concept.






1Arrange the following in the proper order in which they occur.

1. Binding of ligand to receptor site
2. Dissociation of G protein subunits
3. Diffusion of calcium ions into the cell
A)1, 2, 3
B)2, 1, 3
C)2, 3, 1
D)3, 2, 1
E)3, 1, 2



2The activation/inactivation of G proteins occurs as a result of
A)synthesis and hydrolysis of GTP.
B)GDP/GTP exchange and GTP hydrolysis.
C)binding and release of extra G protein subunits.
D)binding and release of Ca2+ ions.
E)binding and release of the ligand.



3Which of the following statements about the protein calmodulin is TRUE?
A)It interacts directly with the ligand receptor.
B)It interacts directly with the G protein.
C)It binds to Ca 2+ ions to mediate a cellular response.
D)It binds to the Ca 2+ ion channel causing it to close.
E)It induces ATP hydrolysis.



4The activity of the G protein mainly resides in the beta ( β ) subunit.
A)True
B)False



5Phosphorylase activity removes a phosphate from GTP.
A)True
B)False







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