Gluconeogenesis

Question 0

3 reactions that require different enzymes and processes from glycolysis

Answer 0

pyruvate to PEP
Fructose1,6 bis-phosphate to fructose 6 phosphate
Glucose 6 phosphate to glucose

Question 1

Average human uses around ___ g of Glucose per day

Answer 1

160

Question 2

three major carbon sources for Gluconeogenesis

Answer 2

Lactate
Amino acids
Glycerol

Question 3

Lactate Dehydrogenase

Answer 3

converts lactate to pyruvate

producing NADH in process

Question 4

Cori cycle

Answer 4

Shuttling of lactate from cells to only place, Liver, where it can be converted into Glucose

Question 5

Two amino acids that do not participate/contribute to Gluconeogenesis

Answer 5

Lysine
Leucine

Amino acids are used to generate pyruvate

Question 6

From fatty acids, Gluconeogenesis uses …

Answer 6

the triacylglycerol portion only

Question 7

Glycerol is used to make …

Answer 7

DHAP

Question 8

GNG occurs during fasting but also during ….

Answer 8

prolonged exercise
high protein diets
stress

Question 9

Major substrates that stimulate GNG

Answer 9

Glycerol
Lactate
Amino acids - released from muscle when insulin levels are low, if from dietary protein then requires Low carb intake as well

Question 10

Conversion of Pyruvate to PEP requires

Answer 10

Pyruvate dehydrogenase is inactive
Pyruvate carboxylase is active
PEPCK is induced

Question 11

Induced vs. Activated enzymes

Answer 11

Activated - enzyme already made and it ready to be turned off/on

Induced - the enzyme needs to be made

Question 12

Biochemically, Fasting leads to low insulin, adipose breaks down, elevated glucagon. The glucagon activates …

Answer 12

Adenylate cyclase which converts ATP to cAMP
cAMP will induce the transcription of PEPCK which converts OAA to PEP
Fatty acids travel to liver and oxidation leads to acetylCoA, NADH and ATP leading to depletion of ADP which inhibits pyruvate dehydrogenase keeping pyruvate from going to the TCA cycle
Acetyl CoA activates pyruvate carboxylase

Question 13

Under non fasting conditions, Epinephrine during stress…

Answer 13

activates adenylate cyclase

Question 14

Glucagon phosphorylates pyruvate kinase to …

Answer 14

inhibit the enzyme and stop the rxn from re-converting PEP back into pyruvate

Question 15

High insulin during fasting leads

Answer 15

to an increase in F2,6 BP, while glucagon leads to a decrease in F2,6BP

Question 16

F2,6BP activates

Answer 16

glycolytic enzyme, Phosphofructokinase
and it inhibits gluconeogenic enzyme F1,6BP

hence fasting leads to inhibition of kinase and activation of phosphatase

Question 17

Glucokinase has high Km for glucose meaning …

Answer 17

low affinity for glucose

Question 18

Insulin ____ more GK

Answer 18

…

Question 19

A patient comes in for a glucose tolerance test. 30 minutes after ingesting a high glucose beverage, which liver enzymes would be active?

Answer 19

Glucokinase and PFK1

Question 20

what enzymes in the gluconeogenic pathway would be inhibited when the glycolytic pathway is activated?

Answer 20

PEPCK 
Fructose 1,6 Biphosphate 
pyruvate kinase 
pyruvate carboxylase 
glucose 6 phosphate

Question 21

Hormonally, what does Fasting do?

Answer 21

decrease insulin and increase glucagon

Question 22

what inhibits glycolysis and promotes gluconeogenesis?

Answer 22

Glucagon
cAMP
acetyl CoA

Question 23

What does cAMP induce transcription of?

Answer 23

PEPCK
Acetyl CoA

these are breakdown products of fatty acid metabolism

which will activate pyruvate carboxylase

Question 24

Fructose 2,6 Bisphosphate will ____ gluconeogenesis and ______ glycolsis

Answer 24

inhibit

promote

Question 25

Describe the hormonal levels in the fed state

Answer 25

high insulin levels occur so glycolysis is favored and gluconeogenesis is inhibited

Question 26

induced vs. active

Answer 26

induced means that enzyme needs to be made

active already made and ready to be turned on or off

Question 27

what is the key starting ingredient for gluconeogenesis?

Answer 27

pyruvate which is formed lactate and amino acids