Glycolysis

pyruvate is converted to acetyl-CoA and enters the TCA cycle

what is pyruvate’s fate under aerobic conditions?

pyruvate can be converted into lactate (animal muscles) or ethanol (yeast); pathways reoxidize NADH to NAD+, which allows glycolysis to continue

what are pyruvate’s two fates under anaerobic conditions?

investment phase

energy is invested in priming reactions to maximize energy production in stage 2

phosphorylation, glucose-6-phosphate

in the investment phase, glucose is activated by _____ making _____

activated

glucose is _____ by phosphorylation, making glucose-6-phosphate in the investment phase

2, glyceraldehyde-3-phosphate

at the end of the investment phase, glucose is converted to _____ molecules of _____

glucose is converted to glucose-6-phosphate (G6P)

step 1 of glycolysis

yes, but does not commit G6P to glycolysis

is step 1 of glycolysis regulated?

phosphorylates glucose to make glucose-6-phosphate

what does hexokinase do?

glucose-6-phosphate is converted to fructose-6-phosphate

step 2 of glycolysis

phosphoglucose isomerase

rearranges the aldose G6P to the ketose F6P

no, it is not a committed step either

is step 2 of glycolysis regulated?

fructose-6-phosphate is converted to fructose-1,6-bisphosphate

step 3 of glycolysis

phosphorylates fructose-6-phosphate to make fructose-1,6-bisphosphate

phosphofructokinase

yes, it’s highly regulated and is the first committed step

is step 3 of glycolysis regulated?

fructose-1,6-bisphosphate is converted to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate

step 4 of glycolysis

fructose bisphosphate aldolase

cleaves the 6C sugar into two 3C sugars in a lyase reaction

no

is step 4 of glycolysis a regulatory step?

dihydroxyacetone phosphate is converted to glyceraldehyde-3-phosphate

step 5 of glycolysis

glucose + 2 ATP —> 2 glyceraldehyde-3-phosphate + 2 ADP + 2Pi

reaction for investment phase of glycolysis

dividend phase

each glyceraldehyde-3-phosphate is converted to pyruvate

glyceraldehyde-3-phosphate is converted to 1,3-bisphosphoglycerate

step 6 of glycolysis

glyceraldehyde-3-phosphate dehydrogenase (GAPDH)

oxidatively adds a phosphate group to 3-GAP and reduces NAD+ to NADH

1,3-bisphosphoglycerate (1,3-BPG)

a high energy acyl phosphate that will be used for ATP synthesis

no

is step 6 of glycolysis regulated?

1,3-bisphosphoglycerate is converted to 3-phosphoglycerate

step 7 of glycolysis

phosphoglycerate kinase

transfers 1-phosphate from 1,3-BPG to ADP through an SN2 reaction

no

is step 7 of glycolysis regulated?

3-phosphoglycerate is converted to 2-phosphoglycerate (2-PG)

step 8 of glycolysis

phosphoglycerate mutase

rearranges 3-phosphoglycerate to 2-phosphoglycerate in an isomerization reaction

no

is step 8 of glycolysis?

2-phosphoglycerate is converted to phosphoenolpyruvate (PEP)

step 9 of glycolysis

enolase

catalyzes a lyase reaction to make the second high-energy compound for ATP production

no

is step 9 of glycolysis regulated?

phosphoenolpyruvate is converted to pyruvate

step 10 of glycolysis

pyruvate kinase

transfers a phosphate from PEP to ATP through an SN2 group transfer reaction

yes, and it’s irreversible

is step 10 of glycolysis regulated?

hexokinase, phosphofructokinase, pyruvate kinase

what are the 3 regulated steps of glycolysis?