Glycolysis
- Created by: Jelena
- Created on: 19-03-13 23:44
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- Glycolysis
- Occurs in the cytoplasm
- Anaerobic
- Needs 2 ATP, yields 4 ATP. Net yield of 2 ATP overall.
- 10 steps
- 1-5 = preparatory phase
- 6-10 = payoff phase
- = "sugar splitting"
- In some cancers, glycolysis is up-regulated
- Cancer cells increase rate of glycolysis so they have enough ATP to keep dividing
- Cellular respiration = C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP
- STAGE 1: Glucose Mobilization/Activation
- 2 ATP required
- Phosphates transferred to glucose via phosphorylation
- ATP converted to ADP
- Glucose turns into fructose 1,6-biphosphate
- Must be cleaved into 2 3-carbon phosphorylated molecules
- STAGE 2: Cleavage/Sugar Splitting
- STAGE 1: Glucose Mobilization/Activation
- 2 ATP required
- Phosphates transferred to glucose via phosphorylation
- ATP converted to ADP
- Glucose turns into fructose 1,6-biphosphate
- Must be cleaved into 2 3-carbon phosphorylated molecules
- Fructose 1,6-biphosphate split into DHAP and G3P
- DHAP turns into G3P
- STAGE 1: Glucose Mobilization/Activation
- STAGE 3: Oxidation
- STAGE 2: Cleavage/Sugar Splitting
- Fructose 1,6-biphosphate split into DHAP and G3P
- DHAP turns into G3P
- Fructose 1,6-biphosphate split into DHAP and G3P
- Both G3P molecules oxidized
- Hydrogen atom from G3P is removed and given to NAD+
- NAD+ becomes NADH
- NADH used to produce energy later --> stores energy like a piggy bank
- Phosphate is attached to the sugars, making them 1,3-biphosphoglycerate
- STAGE 2: Cleavage/Sugar Splitting
- STAGE 4: ATP Generation
- STAGE 3: Oxidation
- Both G3P molecules oxidized
- Hydrogen atom from G3P is removed and given to NAD+
- NAD+ becomes NADH
- NADH used to produce energy later --> stores energy like a piggy bank
- Phosphate is attached to the sugars, making them 1,3-biphosphoglycerate
- Phosphate groups of molecules given to ADP --> creates ATP
- Called substrate level phosphoryation
- Endergonic
- G3P converted into 3 carbon sugar molecule = pyruvate
- 4 ATP made
- STAGE 3: Oxidation
- Glucose becomes pyruvate
- ADP becomes ATP
- Glucose becomes pyruvate
- NAD+ becomes NADH
- ADP becomes ATP
- ADP becomes ATP
- High amounts of glucose? --> inc. rate of glycolysis
- High amounts of pyruvate? --> dec. rate of glycolysis
- No NAD+ to accept H ion? Pathway stops
- High amounts of pyruvate? --> dec. rate of glycolysis
- ATP
- Endergonic, must be driven by exergonic reaction
- PFK
- Catalyses reaction of fructose 6-phosphate to fructose 1,6-biphosphate
- End Product Inhibition inhibits this --> Prevents breakdown of glucose in pathway that makes ATP
- More useful for cell to store glucose as glycogen when there is a lot of ATP
- End Product Inhibition inhibits this --> Prevents breakdown of glucose in pathway that makes ATP
- Enzyme
- Low concentration? --> ATP binds at active site
- High concentration? --> ATP binds at regulatory site --> Inhibits PFK, stop phosphorylationof fructose 6-phosphate
- Catalyses reaction of fructose 6-phosphate to fructose 1,6-biphosphate
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