glycolysis

what are the net products of glycolysis

• two molecules of pyruvate

• two molecules of atp

• two molecules of nad+ reduced to nadh

energy investment stage

• 5 steps

• two molecules of atp are invested

• two molecules of glyceraldehyde 3-phosphate are produced

metabolites used in reduction of nad+

• malate + nad+ → oxaloacetate + nadh + h+

• malate is oxidised by nad+

• oxaloacetate is reduced by nadh

step 1 of glycolysis

• glucose is phosphorylated at position 6

• catalysed by hexokinase

  • one molecule of atp used

step 2 from glucose-6-phosphate

• isomerisation of glucose-6-phosphate to make fructose-6-phosphate

• catalysed by phosphoglucose isomerase

step 3 from fructose-6-phosphate

• second phosphoryl group is transferred from atp to create fructose 1,6-bisphosphate

• catalysed by phosphofructokinase PFK

• one molecule of atp used

which steps in glycolysis use atp

• step1 transfer of phosphoryl group

• step 3 transfer of second phosphoryl group

step 4 from fructose-1,6-bisphosphate

• fructose 1,6-bisphosphate is cleaved to make 2x dihydroxyacetone phosphate

• catalysed by fructose 1,6-bisphosphatase

step 5 from dihydroxyacetone phosphate

• dihydroxyacetone phosphate converted to glyceraldehyde-3-phosphate

• catalysed by triose phosphate isomerase

energy payoff phase

• 4 atp molecules released

• two water molecules reelased

• two nadh released

• generates 2x pyruvate from 2x glyceraldehyde-3-phosphate

step 6 from glyceraldehyde-3-phosphate

• oxidation of glyceraldehyde 3-phosphate and phosphorylation using NAD+

• NAD+ → NADH

• catalysed by glyceraldehyde 3-phosphate dehydrogenase (GADPH)

• to produce 1,3-bisphosphoglycerate

step 7 from 1,3-bipshosphoglycerate

• 1,3,-bisphoshoglycerate → 3-phosphoglyceate

• atp released

• catalysed by phosphoglycerate kinase

step 8 from 3-phosphoglycerate

• 3-phosphpglycerate converted to 2-phosphoglycerate

• catalysed by phosphoglycerate mutase

step 9 from 2-phosphoglycerate

• 2-phosphoglycerate converted to phosphoenolypyruvate

• water released

• catalysed by enolase

step 10 formation of pyruvate

• phosphoenolpyruvate → pyruvate

• substrate level phosphorylation

• catalysed by pyruvate kinase

• atp released

which steps release atp

• step 7

• step 10

how is pyruvate converted to ethanol

• pyruvate → acetaldehyde catalysed by pyruvate decarboxylase

  • co2 released

• acetaldehyde → ethanol catalysed by alcohol dehydrogenase

  • nadh → nad +

lactic fermentation

pyruvate → lactate catalysed by lactate dehydrogenase

• nadh → nad+