L29 Diabetes & Control of Glycogen Metabolism Flashcards
Glycogen metabolism must be…
Tightly regulated!
Allosteric control of glycogen metabolism is…
Slow
There are 3 fast ways to regulate glycogen metabolism…
- Epinephrine
- Glucagon
- Insulin
Epinephrine acts on which receptors in the muscle and liver?
G-protein coupled receptors
Epinephrine binds to G-protein coupled receptors to initiate a…
cAMP dependent phosphorylation cascade resulting in mass breakdown of glycogen
Epinephrine triggers the mass breakdown of glycogen, for what sort of situation?
Emergencies
Insulin and glucagon are secreted from the…
Islet cells of the pancreas
Insulin is produced in the ( β / ⍺ ) islet cells…
β
Glucagon is produced in the ( β / ⍺ ) islet cells…
⍺
The islet cells of the pancreas are highly…
Vascularised
Which is more important to blood sugar regulation…
a) The absolute levels of insulin and glucagon
b) The ratio of insulin to glucagon
c) Only the absolute levels of insulin
b) The ratio of insulin to glucagon
Glucagon binds to receptors in the…
a) Liver and muscle cells
b) Muscle cells
c) Liver cells
c) Liver cells
On binding to the receptor, glucagon has the effect of (4)…
- Increasing glucose release
- Increasing glycogen breakdown
- Increasing gluconeogenesis
- Decreasing glycogen synthesis
Insulin binds to receptors in the…
a) Liver and muscle cells
b) Muscle cells
c) Liver cells
a) Liver and muscle cells
Insulin has the effect of (4)…
- Increasing glucose uptake
- Decreasing glycogen breakdown
- Decreasing gluconeogenesis
- Increasing glycogen synthesis
Both glycogen and insulin can be controlled by…
Phosphorylation
Phosphorylation has what effect on glycogen phosphorylase?
Activation (which leads to glycogen breakdown)
Phosphorylation has what effect on glycogen synthase?
Deactivation (which stops glycogenesis)
Insulin and glucagon:
a) act via G-protein linked receptors
b) act via different receptor types
c) act via enzyme-linked receptors
b) act via different receptor types
Epinephrine and glucagon:
a) act via G-protein linked receptors
b) act via different receptor types
c) act via enzyme-linked receptors
a) act via G-protein linked receptors
Insulin:
a) acts via G-protein linked receptors
b) acts via different receptor types
c) acts via enzyme-linked receptors
c) acts via enzyme-linked receptors
Both epinephrine and glucagon bind to G-Protein linked receptors, initiating a cAMP dependent phosphorylation cascade resulting in the…
- Activation of glycogen phosphorylase
- Deactivation of glycogen synthase
(they both get phosphorylated as part of the cascade, but as mentioned on another question, it has opposite effects on each)
Insulin binds to an enzyme linked receptors known as…
Receptor tyrosine kinase
Receptor tyrosine kinase phosphorylates…
IRS
