Protein phosphorylation is commonly involved with all of the following except

Protein phosphorylation is commonly involved with all of the following except

A) regulation of transcription by extracellular signaling molecules.
B) enzyme activation.
C) activation of G protein-coupled receptors.
D) activation of receptor tyrosine kinases.
E) activation of protein kinase molecules.


Answer: C

Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells?

Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells? 

A) Enzymatic activity was proportional to the amount of calcium added to a cell-free extract.
B) Receptor studies indicated that epinephrine was a ligand.
C) Glycogen breakdown was observed only when epinephrine was administered to intact cells.
D) Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined.
E) Epinephrine was known to have different effects on different types of cells.

Answer: C

Apoptosis involves all but which of the following?

Apoptosis involves all but which of the following? 

A) fragmentation of the DNA
B) cell-signaling pathways
C) activation of cellular enzymes
D) lysis of the cell
E) digestion of cellular contents by scavenger cells



Answer: D

Consider this pathway: epinephrine ? G protein-coupled receptor ? G protein ? adenylyl cyclase ? cAMP. Identify the second messenger.

Consider this pathway: epinephrine ? G protein-coupled receptor ? G protein ? adenylyl cyclase ? cAMP. Identify the second messenger. 

A) cAMP
B) G protein
C) GTP
D) adenylyl cyclase
E) G protein-coupled receptor


Answer: A