Flashcards in Lecture 40 Deck (23):
1
In a fasted state what pathways are on and what pathways are off?
ON
-Gluconeogenesis
-Glycogen breakdown (glycogenolysis)
-Pyruvate carboxylase
-Lipolysis
Off
-Glycolysis
-Pyruvate dehydrogenase
-Glycogen synthesis
-Lipogenesis
2
What enzyme is controlling glycolysis? Gluconeogenesis?
-Citrate controls phosphofruktokinase activity (inhibits)
-Low phosphofruktokinase activity --> low fructose 2,6 P2 --> inc. gluconeogenesis/dec. glycolysis
3
In a fasted state Pyruvate needs to be used to make ____ and not ____.
-oxaloacetate (gluconeogenesis)
-TCA cycle
4
During fasting pyruvate dehydrogenase is ___ while pyruvate carboxylase is ____. This is controlled by _____ that is derived from ______.
-Inactive
-Active (gluconeogenesis)
-Acetyl CoA
-b-oxidation of lipid (lipid breakdown)
5
During fasting lipid breakdown is ___ and lipid synthesis is ____. What controls this?
-Increased
-Decreased
-Long-chain acyl Co-A from b-oxidation blocks acetyl CoA carboxylase which is needed for lipid synthesis to make malonyl CoA
6
During fasted state what two hormones are contributing to stimulating glycogenolysis and gluconeogenesis? What is their mechanism of action?
-Glucagon & Epinephrine
-G-protein receptors --> cAMP --> PKA --> Enzyme phosphorylation --> Inc glycogenolysis/gluconeogenesis; Dec glycolysis/lipogenesis
7
What is the result of phosphorylating the following enzymes:
1. Glycogen phosphorylase
2. Glycogen synthase
3. PFK2
4. Pyruvate Kinase
5. Pyruvate DHase
6. Acetyl CoA Carboxylase
1. On --> glycogen breakdown
2. Off --> glucose storage
3. On --> phosphatase removes F 2,6 P2
4. Off --> inhibits glycolysis
5. Off --> directs pyruvate to gluconeogenesis
6. Off --> turns off lipogenesis
8
AMP is a signal of ____ and ___ as a result of work/hypoxia.
-Energy deprivation
-Rise
9
What is the role of AMPK?
-Activated by high levels of AMP it phosphorylates key enzymes in the cell to promote glycolysis and turn off gluconeogenesis
10
In conditions of work/hypoxia indicate which pathway is increased/decreased:
1. Gluconeogenesis
2. Glycolysis
3. Fatty acid oxidation
4. Lipogenesis
5. Protein synthesis
6. cholesterol genesis
1. Decreased
2. Increased
3. Increased
4. Decreased
5. Decreased
6. Decreased
11
What key enzymes does AMPK phosphorylate?
1. Glycogen synthase
2. Glycerol acyl transferase
3. Acetyl Co-A carboxylase
4. HMG CoA reductase
12
How are enzymes controlled at the gene level in fasted state?
Glucagon --> PKA --> CREB-P --> binds response elements to turn on gluconeogenesis/off lipogenesis
13
In a well fed state what are 3 enzymes that are promoting glycolysis?
1. Glucokinase
2. PFK --> Fructose 2,6 P2
3. Pyruvate Kinase
14
In the well-fed state PDHase is ___ while pyruvate carboxylase is ____.
-active
-inactive
15
In the well-fed state lipogenesis is turned ___ while lipolysis is turned ____. This is controlled by ____ and _____.
-on
-off
-citrate stim of acetyl CoA carboxylase
-malonyl CoA inhibition of b-oxidation
16
In the fasted state glucagon and epinephrine promote enzyme ____ while in the well fed state insulin promotes enzyme _____
-phosphorylation
-dephosphorylation
17
Insulin turns off genes in gluconeogenic and fatty acid oxidation pathway by inhibiting ______ which bind to _____
-forkhead txn factor
-insulin response elements
18
True or False:
Excess glucose can directly regulate gene txn?
True
-Glucose can activate txn factor that is binding to carbohydrate response element (CarRE) which turns on lipogenesis
19
Indicate whether the following enzyme would be active in the fasted or well-fed state:
1. PFK2
2. Malic enzyme
3. Glucose 6-phosphatase
4. Citrate lyase
5. HMG CoA synthase
6. Fructose bis-phosphatase
7. PEP carboxykinase
8. HMG CoA reductase
1.WF
2. WF
3. F
4. WF
5. F
6. F
7. F
8. WF
20
Indicate whether the following enzymes will be active in the fasted or well-fed state:
1. Pyruvate Kinase
2. FA synthase
3. Pyruvate carboxylase
4. Acetyl CoA carboxylase
5. Pyruvate Dehydrogenase
6. Amino transferases
7. Pentose phosphate pathway
8. Carnitine Palmityl transferase
1. WF
2. WF
3. F
4. WF
5. WF
6. F
7. WF
8. F
21
Carnitine is used by the ___ but synthesized in the _____
-Heart and muscle
-Kidney and liver
22
How is carnitine formed?
Proteolysis of proteins that contain a tri-methyl lysine.
-TML portion becomes carnitine
23