Chapter 22 (Gluconeogenesis Regulation)

Question 1

PFK, FBPase, Pyruvate Kinase and Pyruvate Carboxylase are examples of ___

Answer 1

Allosteric regulators

Question 2

Hormonal regulation (glucagon/insulin) PFK-2, FBPase-2 and Pyruvate Kinase (liver) are examples of ___

Answer 2

Covalent Modification

Question 3

Pancreatic islets hormones

Answer 3

alpha cells - glucagon

beta cells - insulin

Question 4

Glucagon

Answer 4

Low blood sugar
Activates phosphorylation cascade
Activates liver gluconeogenesis
Acts in liver and adipose tissue only

Question 5

Insulin

Answer 5

High blood suger
Activates dephosphorylation cascade
Inhibits liver gluconeogenesis
Increases glucose transportation into cells

Question 6

GLUT2

Answer 6

Found in the liver and pancreas
Pancreas: regulates insulin
Liver: removes excess glucose from the blood

Question 7

GLUT4

Answer 7

Found in muscle and fat cells

Amount in muscle increases with endurance training

Question 8

Hexokinase in the muscle is ___ inhibited by ___

Answer 8

Allosterically
Glucose-6P (product)
Increased levels of G-6P decrease hexokinase activity

Question 9

Glucokinase only turns on when the cell is rich in ___

Answer 9

glucose

Increased glucose = increased glucokinase activity

Question 10

Glucagon phosphorylates ___

Answer 10

Pyruvate kinase (makes it inactive)
By doing this it saves 2 ATP
Puts focus on gluconeogenesis

Question 11

Pyruvate Carboxylase regulation

Answer 11

Increased levels of Acetyl-CoA activates Pyruvate Carboxylase

Question 12

Phosphofructokinase (PFK) exists in two conformational states

Answer 12

T/R

Question 13

High levels of ATP shift PFK in favor of the ___ state decreasing its affinity for ___. To stop this inhibition we need ___, ___, and ___

Answer 13

T
Fructose-6P
AMP, ADP, and Fructose-2,6-BP

Question 14

Phosphofructokinase (PFK) regulation

Answer 14

Increased levels of ATP and citrate deactivate it

Increased levels of AMP, ADP and Fructose-2,6-bisphosphate activate it

Question 15

Small changes in ATP concentration results in large changes in ___ and ___ concentrations

Answer 15

ADP and AMP

Question 16

The concentration of ATP is highly regulated by ___ and ___

Answer 16

creatine kinase

adenylate kinase

Question 17

Fructose-2,6-bisphosphate allosteric regulation

Answer 17

Increases Phosphofructokinases (PFK) affinity for Fructose-6P
Decreases Fructose bisphosphatases affinity for Fructose-1,6-BP

Question 18

Cellular concentration of Fructose-2,6-BP is a reflection of the ___ level in the blood

Answer 18

Glucagon

Question 19

The activites of Phosphofructokinase-2 and Fructose Bisphosphatate-2 are under ___ control

Answer 19

hormonal

Question 20

Glucagon (activates/inactivates) PFK-2

Insulin (activates/inactivates) PFK-2

Answer 20

inactivates it (through phosphorylation)
activates it (through dephosphorylation) 
All occurs in the LIVER

Question 21

In the HEART when AMP concentrations are HIGH, PFK-2 is ___ and thereby activated

Answer 21

phosphorylated

Question 22

Fructose hormonal regulation in the liver

Answer 22

Fructose does not use PFK in the liver, therefore if insulin is released to decrease blood sugar it will not have and effect on fructose breakdown