3. Adrenaline and Secondary Messengers

Question 1

define adrenaline

Answer 1

hormone which prepares your body for fight or flight, released by the adrenal glands

Question 2

define the second messenger model

Answer 2

the way a non-lipid soluble molecule (glucagon or adrenaline) triggers the production of a secondary messenger such as AMP

Question 3

name two ways that glycogenolysis can be activated in liver cells

Answer 3

1. with glycogen
2. with adrenaline

Question 4

outline the activation of glycogenolysis with glycogen

Answer 4

• glucagon binds to liver cell membrane receptors
• G protein is activated, activating the enzyme adenylyl cyclase by changing its shape
• adenylyl cyclase converts ATP to cyclic AMP
• cyclic AMP acts as the second messenger and initiates protein kinases
• protein kinase enzymes catalyses glycogenolysis (breakdown of glycogen to glucose)

Question 5

outline the activation of glycogenolysis with adrenaline

Answer 5

• adrenaline is a hormone which binds to different receptors on liver cells to glucagon
• adenylyl cyclase changes shape and becomes activated
• this catalyses the conversion of ATP to cyclic AMP
• cyclic AMP initiates protein kinases
• which activates glycogenolysis