Glycolysis and Gluconeogenesis

Question 1

Anaerobic vs aerobic metabolism

Answer 1

Anaerobic: net 2 ATP (RBCs sole energy)

Aerobic:
malate-aspartate shuttle (heart, liver, kidney) net 32 ATP
Glycerol – phosphate shuttle (brain, sk.m. cells) – net 30 ATP

Question 2

Hexokinase vs glucokinase

Answer 2

Phosphorylate glucose to G6P to trap in cell

Hexokinase: all cells – low km, higher affinity for glucose, low capacity, low vmax
-NOT induced by insulin

Glucokinase: regulate glucose – Liver, beta cells
-high km, high v max, induced by insulin

Question 3

GLUT1

Answer 3

RBC, endothelium of BBB
Mediates basal glucose uptake
Regardless of insulin

Question 4

GLUT2

Answer 4

Hepatocytes
Pancreatic B cells
Regulate glucose

Question 5

GLUT3

Answer 5

Neurons

Placenta

Question 6

GLUT4

Answer 6

Sk.m.
Adipose tissue
Requires insulin

Question 7

GLUT5

Answer 7

Fructose uptake in GI tract

Question 8

Draw glycolysis and gluconeogenesis pathway

Answer 8

Page 531/536

Question 9

Rate limiting enzyme of glycolysis

Answer 9

Phosphofructokinase 1

Question 10

Glycolytic enzyme deficiency

Answer 10

Presentation: hemolytic anemia d/t inability to maintain Na/K ATPase -> RBC swelling/lysis

Common cause: pyruvate kinase deficiency

Question 11

Draw regulation of glycolysis pathway

Answer 11

Page 532

Question 12

Draw glucagon effects on glycolysis/gluconeogenesis

Answer 12

Page 533

High glucagon -> more active protein kinase A -> active FBP2 = less Fru 2,6 bisP -> less active PFK1 -> less glycolysis

Low glucagone (high insulin) -> less active protein kinase A -> active PFK2 -> more fru-2,6-bisP -> active PFK1 -> more glycolysis

Question 13

Gibbs free energy

Answer 13

Delta G = delta H – Tdelta S

Question 14

Substrates entering to make pyruvate

Answer 14

Odd chain FAs -> propionyl – CoA -> pyruvate

TCA cycle molecules -> pyruvate or oxaloacetate

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