Energy Metabolism Flashcards
Major fuel sources for skeletal muscle
Glucose and fatty acids
Primary energy source during fasting in skeletal muscles
Fatty acids
Describe fast-twitch muscles
Larger muscles, low high ATPase, white, low myoglobin, short term high intensity exercises, easily fatigues
Describe slow-twitch muscles
Smaller muscles, low ATPase, red, high myoglobin, prolonged, moderate exercise, not easily fatigued
Where is hexokinase found?
Widely distributed in tissues
Where is Glucokinase found?
Only in hepatocytes and pancreatic cells.
rate limiting enzyme in glycolysis
Phosphofructokinase I that converts fructose-6-phosphate to frutose- 1,6-bisphosphate
How is phosphofructokinase I activated?
Insulin activates PFK2 which makes F2,6P which activates PFK1
How is phosphofructokinase inhibited?
Glucagon inhibits PFK2 which lowers F2,6P which inhibits PFK1
Produced through the reaction of glyceraldehyde 3-phosphate dehydrogenase
Conversion of NAD to NADH
Produced through the reaction of 3 phosphoglycerate kinase
Conversion of ADP to ATP
Produced through the reaction of pyruvate kinase
Conversion of ADP to ATP
Activator of pyruvate kinase
Fructose 1,6 bisphosphate from PFK1 reaction
How does lactate dehydrogenase continue glycolysis?
LDH converts NADH to NAD, releasing the coenzyme needed for glyceraldehyde-3-phosphate dehydrogenase
2 Electron Shuttles
Malate shuttle - NADH
Glycerol phosphate shuttle- FADH2
Pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase complexes are made up of which enzymes?
pyruvate dehydrogenase/decarboxylase , Dihydrolipoyl transacetylase and Dihydrolipoyl dehydrogenase
What amino acids are incorporated into the TCA and where?
Alanine- pyruvate
Aspartate- oxaloacetate
phenylalanin/tyrosine- fumarate
Valine, Methionine, Isoleucine & threonin - succinyl CoA
Glutamine - alpha ketoglutarate
Inhibitors of PFK1
ATP and citrate
Activators of PFK1
AMP, Fructose 2,6 Bisphosphate
Activators of carbamoyl phosphate synthetase II
ATP and PRPP
Which enzyme is inhibited by glucose 6 phosphate?
Hexokinase
Which enzyme is inhibited by fructose 6 phosphate?
Glucokinase
Activator of pyruvate kinase
Fructose-1,6-bisphosphate