M1-C1-L46 --> Gluconeogenesis

Front 1

In gluconeogenesis, the 7 reversed steps of glycolysis have physiological ΔG at what value?

Back 1

Near zero

Front 2

In gluconeogenesis, the 3 non-reversed steps of glycolysis have physiological ΔG at what value?

Back 2

Less than zero, thus exergonic.

Front 3

What are the only two amino acids that can not feed into gluconeogenesis?

Back 3

leucine and lysine

Front 4

Gluconeogenic, TCA intermediates get funneled through which molecule?

Back 4

oxaloacetate

Front 5

In gluconeogenesis, hexokinase is circumvented by what enzyme?

Back 5

glucose 6 phosphatase

Front 6

In gluconeogenesis, PFK1 is circumvented by what enzyme?

Back 6

Fructose 1,6-bisphosphate (FBP-1)

Front 7

In gluconeogenesis, pyruvate kinase is circumvented by what enzyme?

Back 7

1.) Pyruvate carboxylase
2.) Phosphoenolpyruvate Carboxykinase (PEPCK)

Front 8

How does Acetyl CoA drive pyruvate?

Back 8

1.) It can drive towards gluconeogenesis by activating pyruvate carboxylase (thus converting pyrvate to oxaloacetate).
2.) It can inhibit drive towards TCA by inhibiting Pyruvate Dehydrogenase Complex

Front 9

In the first bypass stage of gluconeogenesis, what must be formed and from what? Also include the intermediate.

Back 9

PEP must be formed from Pyruvate via oxaloacetate.

Front 10

How does oxaloacetate leave the mitochondria? 3 steps

Back 10

1.) Must first oxaloacetate must be converted to malate.
2.) Then go through the malate shuffle.
3.) Then reoxidized to oxaloacetate.

Front 11

In order for pyruvate to convert to oxaloacetate, what other players must be present? X 4

Back 11

1.) ATP (hydrolyzed to ADP)
2.) Bicarbonate
3.) Biotin
4.) Pyruvate Carboxylase

Front 12

What activates pyruvate?

Back 12

The addition of CO2

Front 13

What two major events occur in the converting of oxaloacetate to PEP?

Back 13

1.) Decarboxylation (loss of CO2)
2.) Phosphorylation

Front 14

What are the players needed to convert oxaloacetate to PEP?

Back 14

1.) PEPCK
2.) GTP (phosphorylates)

Front 15

The two consecutive reactions to convert pyruvate to PEP (via oxaloacetate) are what kind of reactions in terms of energy?

Back 15

Exergonic

Front 16

What is the strategic purpose of transferring oxaloacetate from the mitochondria to the cytosol via malate shuttle?

Back 16

To maintain reducing equivalents (NADH) in the cytosol

Front 17

Describe the short route to PEP.

Back 17

The liver specializes in the short route with enzymes already in the mitochondria, thus creating PEP in the MITO.

Front 18

Why does alcohol consumption for undernourished or after strenuous exercise cause low blood glucose levels (hypoglycemia)?

Back 18

Alcohol in the blood will become oxidized by NAD (which will become reduced to NADH). NADH in large cytosol quantities, in the presence of oxaloacetate (or pyruvate) will convert to malate (or lactate). This means that oxaloacetate and pyruvate will be unable to support gluconeogenesis

Front 19

What is the enzyme associated with the second bypass in gluconeogenesis?

Back 19

Fructose bisphosphatase (FBP-1)

Front 20

What are the regulators for FBP-1?

Back 20

AMP and F2,6P

Front 21

What are the two major regulatory activities of F2,6P?

Back 21

1.) Allosterically activates PFK-1
2.) Inhibits FBPase-1

Front 22

How does F2,6P regulate?

Back 22

Reciprocally

Front 23

What regulates F2,6P?

Back 23

1.) PFK-2 (with ATP) increases levels
2.) FBP-2 decreases levels

Front 24

Glucose 6 Phosphatase is not found where?

Back 24

Brain and muscle (thus gluconeogenesis does not occur here)

Front 25

Describe the actions G6Pase in gluconeogenesis.

Back 25

Releases phosphate group liberating free glucose

Front 26

What is the physiological ΔG for glycolysis? Is this reaction favorable?

Back 26

-63 kJ/mol. Favorable

Front 27

What is the physiological ΔG for gluconeogenesis? Is this reaction favorable?

Back 27

-16 kJ/mol. Favorable

Front 28

Increase of Insulin/Glucagon ration does what?

Back 28

Decreases cAMP and Protein Kinase A levels

Front 29

Decreased levels of cAMP and Protein Kinase A favors what state and activity?

Back 29

The dephosphorylated state of PFK-2/FBP-2 complex, meaning that PFK-2 is active and FBP-2 is inactive.

Front 30

The active PFK-2 means increased creation of what?

Back 30

Creation of F2,6P

Front 31

Increased creation of F2,6P means what?

Back 31

Increased activity of PFK-1 leading to drive towards glycolysis.

Front 32

Decrease of Insulin/Glucagon ration leads to what?

Back 32

Increase of cAMP and Protein Kinase A levels.

Front 33

Increased cAMP and Protein Kinase A leads to what?

Back 33

Leads to phosphorylated state of PFK-2/FBP-2 complex.

Front 34

What does the phosphorylated PFK-2/FBP-2 mean?

Back 34

Active FBP-2, and inactive PFK-2

Front 35

Active FBP-2 means what?

Back 35

Decreases the amount of F2,6P

Front 36

Decreasing the amount of F2,6P leads to what?

Back 36

DErepressing the FBPase-1, thus promoting gluconeogenesis.

Front 37

PFK-2/FBP-2 is what type of protein?

Back 37

A single bifunctional protein

Front 38

What are the long term effects of glucagon genetically

Back 38

Represses the genes encoding the three regulatory enzymes of glycolysis IN THE LIVER

Front 39

How much energy is required to convert 2 lactate molecules to 1 glucose molecule?

Back 39

6 ATP

Front 40

How much is required to convert glucose to lactate?

Back 40

2 ATP

Front 41

T/F - The brain does not fully oxidize glucose thus it will funnel back lactate.

Back 41

FALSE. It fully oxidizes the glucose

Front 42

What does the Cori Cycle shuttle and to where?

Back 42

Glucose and lactate between the liver and muscle/RBC

Front 43

Describe the Alanine cycle.

Back 43

Alanine is transanimated to become pyruvate which will go through gluconeogenesis to become glucose.

Front 44

How much glucse is needed by the brain, muscle, and RBC's a day?

Back 44

120 g