1.) Which of the following is not involved in signal transduction by the b -adrenergic receptor pathway?

A) ATP

B) Cyclic AMP

C) Cyclic GMP

D) GTP

E) All of the above are involved.

2.) Which of the following is not involved in signal transduction by the b -adrenergic receptor pathway?

A) Cyclic AMP synthesis

B) GTP hydrolysis

C) GTP-binding protein

D) Protein kinase

E) All of the above are involved.

3.) Calmodulin is a(n):

A) allosteric activator of calcium-dependent enzymes.

B) allosteric inhibitor of calcium-dependent enzymes.

C) calcium-dependent enzyme.

D) cell surface calcium receptor.

E) regulatory subunit of calcium-dependent enzymes.

4.) Which of the following statements concerning signal transduction by the insulin receptor is not correct?

A) Activation of the receptor protein kinase activity results in the activation of additional protein kinases.

B) Binding of insulin to the receptor activates a protein kinase.

C) Binding of insulin to the receptor results in a change in its quaternary structure.

D) The receptor protein kinase activity is specific for tyrosine residues on the substrate proteins.

E) The substrates of the receptor protein kinase activity are mainly proteins that regulate transcription.