Lecture 6 - Pulling for the same team

What is gluconeogenesis?

making glucose from non carbohydrate sources

Where does gluconeogenesis mainly occur?

liver

What are the main starting materials for gluconeogenesis?

pyruvate, lactate, glycerol, amino acids

Why can't glycolysis simply run backwards?

three reactions are irreversible and require different enzymes

Which enzymes are involved in bypass 1?

pyruvate carboxylase, PEPCK

What does pyruvate carboxylase do?

convert pyruvate into oxalocetate

What does PEPCK do?

converts oxaloacetate into PEP

How does oxaloacetate leave the mitochondria?

converted into malate, transported out and converted back

What does fructose-1,6-bisphosphatase do?

converts into fructose-6-phosphate

What does glucose-6-phosphatase do?

converts into free glucose

Why can't skeletal muscle release glucose into the blood?

lacks glucose 6 phosphatase

What is reciprocal regulation?

glycolysis and gluconeogenesis are regulated in opposite directions

What is a futile cycle?

opposing pathways running simultaneously and wasting energy

What does high AMP indicate?

low cellular energy

What does high AMP do to metabolism?

activates glycolysis and inhibits gluconeogenesis

What does high ATP do to glycolysis?

inhibits it

What are the effects of high acetyl-CoA?

activates pyruvate carboxylase, inhibits pyruvate dehydrogenase and pyruvate kinase

Which two enzymes are major control points of glycolysis in skeletal muscle?

pfk and pyruvate kinase

How much energy does gluconeogenesis require to make one glucose from two pyruvate?

4 atp and 2 gtp

How much energy is wasted in a futile cycle?

4 atp equivalents