Glycolysis Flashcards
What is the general reaction for glycolysis?
Glucose > 2 pyruvate
Where in a cell does glycolysis occur?
Cytosol
What are the 4 stages of glycolysis?
Activation - uses ATP
Splitting of the 6 carbon molecule into two 3 carbon molecules
Oxidation - removing 2 H atoms
Synthesis of ATP
What are the 3 reactions in the activation stage?
glucose > glucose-6-phosphate > fructose-6-phosphate > fructose-1,6,-bisphosphate
What enzyme converts glucose to glucose-6-phosphate?
Hexokinasese - in nearly all cells.
Glucokinase - in liver and beta-cells of the pancreas
What enzyme converts glucose-6-phosphate to fructose-6-phosphate?
Phosphoglucose isomerase
What enzyme converts fructose-6-phosphate to fructose-1,6-bisphosphate?
Phosphofructokinase
What are the products of the hydrolysis of fructose-1,6-bisphosphate?
glyceraldehyde-3-phosphate
dihydroxyacetone phosphate
What enzyme catalyses the hydrolysis of fructose-1,6-bisphosphate?
Aldolase A
What enzyme converts dihydroxyacetone phosphate into glyceraldehyde-3-phosphate?
Triose phopshate isomerase
What is the oxidation reaction in glycolysis?
Glyceraldehyde-3-phosphate > 1,3-bisphosphoglycerate
What enzyme catalyses the oxidation reaction of glyceraldehyde-3-phosphate into bisphosphoglycerate using NAD+?
Glyceraldehyde-3-phosphate dihydrogenase
What are the series of reactions in ATP production in glycolysis?
1,3-bisphosphate > 3-phosphoglycerate > 2-phosphoglycerate > phosphoenol pyruvate > pyruvate
Which reactions produce ATP from ADP?
1,3-bisphosphate > 3-phosphoglycerate
and
phosphoenol pyruvate > pyruvate
What is the enzyme which catalyses the reaction of 1,3-bisphosphate into 3-phosphoglycerate?
Phosphoglycerate kinase
What enzyme catalyses the reaction of 3-phosphoglycerate into 2 phosphoglycerate?
Phosphoglycerate mutase
What enzyme catalyses the reaction of 2-phosphoglycerate into phosphoenol-pyruvate?
Enolase
What enzyme catalyses the reaction of phosphoenol-pyruvate into pyruvate?
Pyruvate kinase
What sort of reaction is 2-phosphoglycerate > phosphoenol pyruvate?
Dehydration reaction
Which reactions in glycolysis are irreversible?
Hexose (glucose > glucose-6-phosphate)
Phosphofructokinase (fructose-6-phosphate > fructose-1,6-bisphosphate)
Pyruvate kinase (phosphoenol pyruvate > pyruvate)
In the absense of O2 what happens to pyruvate?
Pyruvate (C=O) is reduced to lactate (C-OH) using NADH.
Pyruvate + NADH + H+ > Lactate + NAD+
What is the enzyme that reduces pyruvate to lactate?
Lactate dehydrogenase
What is the function of lactate dehydrogenase?
Regeneration of NAD+ using NADH + pyruvate.
Produces lactate
Describe the importance of glycolysis in red blood cells.
In erythrocytes there are no mitochondria so aerobic respiration cannot occur nor can the cell use triacylglycerides to generate energy. Hence the erythrocyte can only use glycolysis to release energy.
Where would fructose enter the glycolysis pathway?
Fructose is phosphorylated to fructose-1-phosphate. Catalysed by fructokinase
Where would galactose enter the glycolysis pathway?
It is converted to glucose-6-phosphate in a 4 step reaction.
Galactose > Galactose-6-phosphate + UTP glucose > UTP-galactose + glucose-6-phosphate
UTP-galactose > UTP-glucose
