L13: Glycolysis Flashcards
Key points of glycolysis
Glycolysis
- Definition:
- Location:
- Tissues:
- Functions:
- Glucose C6 -> 2 pyruvate C3
- Cytosol
- All tissues
- ‘Energy’ trapping
3 functions of glycolysis
- ‘Energy’ trapping (ATP synthesis)
- Intermediates for fat synthesis
- Intermediates for amino acid synthesis
Sources of glucose for glycolysis
- Sugars & starch from diet
- Breakdown of stored glycogen from liver
- Recycled glucose
4 stages of glycolysis
- Activation (using up ATP)
- Splitting 6C sugar in half
- Oxidation (removing 2H atoms)
- Synthesis of ATP
Glycolysis
Describe Reaction 1 in glycolysis
- Glucose is trapped within cells by adding negatively charged phosphate
- ATP is used to attach phosphate ‘ATP’ catalysed by hexokinase
What happens in Reaction 1 of glycolysis?
D-glucose uses ATP to attach a phosphate catalysed by hexokinase to produce **glucose 6-phosphate **
What happens in reaction 2 of glycolysis?
Glucose 6-phosphate is catalysed by **phosphohexose isomerase **to produce **fructose 6-phosphate **
DESCRIBE reaction 2 in glycolysis
Switch from aldose to ketose sugar
What happens in Reaction 3 of glycolysis?
Fructose 6-phosphate is catalysed by PFK using ATP to produce fructose 1,6-biphosphate
Reaction 4
What happens during the splitting of 6C to 3C?
Fructose 1,6-biphosphate is split in half using Aldose to produce GaP & DhaP
Reaction 5: Splitting 6C to 3C
Function of triose phosphate isomerase
Catalyse the reaction to convert DhaP to GaP
Reaction 6: Oxidation
What happens during oxidation stage?
GaP uses NAD+ which is catalysed by GaPah to produce 1,3-biphosphoglycerate
Reaction 6
Describe oxidation stage
NaDH produced in this stage will be used in oxidative phosphorylation to generate ATP
What happens in Reaction 7 of glycolysis?
1,3-biphosphoglycerate catalysed by phosphoglycerate kinase & uses 2x ATP to produce 3-phosphoglycerate
How does ATP form from ADP by substrate level phosphorylation?
Substrate-level phosphorylation is the direct formation of ATP or GTP by transferring a phosphate group from a high energy compound to an ADP or GDP molecule.
What happens in Reaction 8- isomerisation in glycolysis?
3-phosphoglycerate catalysed by phosphoglycerate mutase to produce 2-phosphoglycerate
Phosphate moved around
What happens during Reaction 9 of glycolysis?
2-Phophoglycerate releases H2O and catalysed by enolase to produce PEP (phosphoenol pyruvate)
What happens during Reaction 10 (Substrate level phosphorylation)?
PEP produces ATP and catalysed by pyruvate kinase (irreversible enzyme) to produce pyruvate
Define substrate level phosphorylation
Substrate-level phosphorylation is the direct formation of ATP or GTP by transferring a phosphate group from a high energy compound to an ADP or GDP molecule
Define anaerobic glycolysis
Transformation of glucose to lactate when limited amounts of oxygen (O2) are available.
Equation for anaerobic glycolysis
Pyruvate + NADH + H+ -> NAD+ + lactate
Role of lactate dehydrogenase in muscle
Catalyse the interconvention of pyruvate to lactate
What happens in lactate dehydrogenase?
Reversible reaction that uses NADH to convert pyruvate to lactate
Specialised functions in skeletal muscle
ATP production during intense exercise
Specialised functions in red blood cells
Only pathway for ATP production
Specialised functions in brain
Major source of ATP
