Gluconeogenesis

Question 1

What enzyme(s) are involved in Bypass 1 of gluconeogenesis?

Answer 1

PEPCK and pyruvate carboxylase

Question 2

What enzyme(s) are involved in Bypass 2 of gluconeogenesis?

Answer 2

Fructose-1,6-bisphosphate

Question 3

What enzyme(s) are involved in Bypass 3 of gluconeogenesis?

Answer 3

Glucose-6-phosphatase

Question 4

What are “bypasses” in gluconeogenesis?

Answer 4

The reverse reactions of the highly regulated reactions of glycolysis

Question 5

How many ATPs, GTPs, and NADHs are spent in gluconeogenesis?

Answer 5

4 ATP, 2 GTP, 2 NADH

Question 6

How many cellular components does gluconeogensis span?

Answer 6

3

Question 7

What are the cellular components that gluconeogenesis spans?

Answer 7

Mitochondrial matrix, cytosol, ER

Question 8

What is the role of pyruvate carboxylase?

Answer 8

It adds carbon to pyruvate.

Question 9

What enzyme does Acetyl-CoA allosterically activate?

Answer 9

Pyruvate carboxylase

Question 10

What is the cofactor of pyruvate carboxylase?

Answer 10

Biotin

Question 11

What is the role of biotin?

Answer 11

It transfers CO2 from HCO3- onto pyruvate

Question 12

What kind of reaction is the pyruvate carboxylase reaction?

Answer 12

Anaplerotic

Question 13

What is pyruvate converted to in Bypass 1?

Answer 13

Oxaloacetate

Question 14

What is oxaloacetate converted to?

Answer 14

Malate

Question 15

How is malate transported to the cytoplasm?

Answer 15

The malate-aspartate shuttle

Question 16

What is malate converted back to in the cytosol?

Answer 16

Oxaloacetate

Question 17

What is oxaloacetate converted to in the cytosol?

Answer 17

PEP

Question 18

What enzyme helps produce PEP?

Answer 18

PEPCK

Question 19

How does PEPCK help produce PEP?

Answer 19

It phosphorylates and decarboxylates oxaloacetate

Question 20

What does Fructose-1,6-Bisphosphatase produce?

Answer 20

Fructose-6-phosphate

Question 21

Is the FBPase-1 reaction favorable?

Answer 21

Yes

Question 22

What does glucose-6-phosphatase do?

Answer 22

It cleaves off the phosphate group, so it releases free glucose

Question 23

Where is glucose-6-phosphatase used?

Answer 23

Glycogen metabolism and gluconeogenesis

Question 24

Where is glucose-6-phosphatase localized?

Answer 24

ER membrane

Question 25

Why is glucose-6-phosphatase localized in the ER membrane?

Answer 25

Because once glucose is created, it is prone to being broken down by the glycolytic enzymes in the cytosol

Question 26

What is the structure of glucose-6-phosphatase?

Answer 26

9 transmembrane helices

Question 27

What helps with transport of glucose?

Answer 27

Hexokinase IV and GLUT2

Question 28

How is reciprocoal regulation of the irreverisble reactions in glycolysis and gluconeogenesis achieved?

Answer 28

Kinetic control

Question 29

What enzyme regulates PFK-1 and FBPase-1?

Answer 29

Fructose-2,6-bisphosphate

Question 30

What does Fructose-2,6-bisphosphate activate?

Answer 30

PFK-1

Question 31

What does Fructose-2,6-bisphosphate inhibit?

Answer 31

Fructose-1,6-bisphosphatase

Question 32

What does PFK-1 activate?

Answer 32

Fructose-1,6-bisphosphate

Question 33

What does Fructose-1,6-bisphosphatase activate?

Answer 33

Fructose-6-phosphate

Question 34

What are PFK-2 and FBPase-2 regulated by?

Answer 34

Fructose-6-phosphate

Question 35

What enzyme is activated in the fed state?

Answer 35

PFK-2

Question 36

What does PFK-2 promote?

Answer 36

Glycolysis

Question 37

Is PFK-2/FBPase-2 phosphorylated or dephosphorylated in the fed state?

Answer 37

Dephosphorylated

Question 38

Is PFK-2/FBPase-2 phosphorylated or dephosphorylated in the fasted state?

Answer 38

Phosphorylated

Question 39

What enzyme is activated when PFK-2/FBPase-2 is phosphorylated?

Answer 39

FBPase-2, thus producing F-6-P, and going through gluconeogenesis

Question 40

What enzyme is activated when PFK-2/FBPase-2 is dephosphorylated?

Answer 40

PFK-2, thus producing F-2,6-BP, and going through glycolysis