MB - Metabolic Control via Enzyme Regulation II

Question 1

In the presence of insulin, what happens to the 3 enzymes: Phosphorylase Kinase, Glycogen Phosphorylase and Glycogen Synthase?

Answer 1

All Dephosphorylated
(-) Phosphorylase Kinase
(-) Glycogen Phosphorylase (less glycogenolysis)
(+) Glycogen Synthase (increased glycogenesis)

Question 2

How does phosphorylation open up the TG droplet?

Answer 2

Phosphorylation changes the shape of the Perilipin coat and opens up the TG droplet
* TG –> FA

Question 3

How is the production of F-2,6-P₂ controlled?

Answer 3

Insulin:
* PFK₂ is active, F-2,6-P₂ is produced

Glucagon:
* FBPase2 is active, F-2,6-P₂ is broken down

Question 4

What is the function AMP-activated protein kinase (AMPK)

Answer 4

Acts as an energy sensor

• Links allosterism to phosphorylation

Question 5

How do transcription factors alter expression?

Answer 5

Bind genes which alter expression

Question 6

What are 2 ways transcription factors are activated?

Answer 6

1. Metabolite Receptors- gene binding after metabolite binds
2. Phosphorylation of TFs- –> gene binding

Question 7

What do Lipoprotein Lipases do?

Answer 7

Cleaves off fatty acids, which enter cells

Question 8

Describe the structure of caffeine?

Answer 8

Purine (similar to adenine and guanine)

Question 9

What does caffeine do?

Answer 9

Acts to inhibit cAMP phosphodiesterase
–> More protein kinase A
–>Phosohorylase a active
* Glycogenolysis and Lipolysis occur