Cell Communication

Which of the following correctly describes the reception stage of this signal transduction pathway?

• epinephrine binds to a g-protein coupled receptor protein present in the cell membrane
• the g protein changes shape, is activated, activates adenyl cyclase, which activates cAMP, which activates protein kinases
• protein kinases phosphoylate molecules
• glycogen synthesis is inhibited and glycogen breakdown is promoted

Which of the following correctly describes the transduction stage of this signal transduction pathway?

• epinephrine binds to a g-protein coupled receptor protein present in the cell membrane
• the g protein changes shape, is activated, activates adenyl cyclase, which activates cAMP, which activates protein kinases
• cAMP binds to the g-protein coupled receptor protein
• glycogen synthesis is inhibited and glycogen breakdown is promoted

Which of the following correctly describes the response stage of this signal transduction pathway?

• epinephrine binds to a g-protein coupled receptor protein present in the cell membrane
• the g protein changes shape, is activated, activates adenyl cyclase, which activates cAMP, which activates protein kinases
• cAMP binds to the g-protein coupled receptor protein
• glycogen synthesis is inhibited and glycogen breakdown is promoted

What is a G protein?

• specific type of membrane-receptor protein
• protein on the cytoplasmic side of a membrane
• membrane-bound enzyme
• relay protein

A G-protien coupled receptor becomes activated when

• GTP displaces GDP

• a signaling molecule binds to the receptor

• G protein releases its receptor

• once the enzyme is activated

Receptor proteins can be found in the

• nucleus

• cytosol

• cell membrane

• all of the above

Which molecule will most likely diffuse across plasma membrane?

• glucose

• carbon dioxide

• sodium ion

• DNA

In eukaryotic cells, which is a second messenger that is produced as a response to an external signal such as a hormone?

• cyclic AMP

• glycogen

• glucose

• epinephrine

The source of the phosphate for a phosphorylation cascade is...

• cAMP

• protein kinase

• ATP

• GTP

Which of the following can activate a protein by transferring a phosphate group to it?

• cAMP
• G Protein
• protein kinase
• protein phosphatase