Glycolysis Flashcards
In catabolism, what do glucose, fatty acids & amino acids all converge to make
Simple 2C Acetyl CoA
What is the major source of metabolic energy in brain, RBCs, renal medulla, sperm
D-Glucose
What is the energy yielded in complete oxidation of glucose
-2840 kJ/mol
What are the 4 major pathways of glucose utilisation
- Storage - glycogen, starch, sucrose
- Oxidation via glycolysis - pyruvate
- Oxidation via pentose phosphate pathway - ribose 5-phosphate
- Synthesis of structural polymers - extracellular matrix & cell wall polysaccharides
What process is responsible for the largest flux of carbon in cells
Glycolysis
What happens in glycolysis - simplified
6C glucose oxidised to 2x 3C pyruvate in the cell cytosol
Where in the cell does glycolysis occur
Cytosol
What is the total energy gained after glycolysis
2ATP & 2NADH
What kind of pathway is glycolysis
Exergonic - releases energy
Glycolysis enzyme 1
Hexokinase
What happens in step 1 of glycolysis
Glucose phosphorylated on position 6 (ATP donates the phosphate)
Glucose -> Glucose 6-phosphate
What does hexokinase need to shield the terminal phosphate from hydrolysis
Mg2+
What is the enzyme in step 2 glycolysis
Phosphohexose isomerase
What happens in step 2 glycolysis
Glucose 6-phosphate isomerises to Fructose 6-phosphate in presence of phosphohexose isomerase enzyme
What do you have at the end of step 2 glycolysis
Fructose 6-phosphate
Enzyme 3 glycolysis
Phosphofructokinase-1
What happens in step 3 glycolysis
Fructose 6-phosphate is phosphorylated to Fructose 1-6- bisphosphate (ATP donates the phosphate)
What do you have at the end of step 3 glycolysis
Fructose 1-6- bisphosphate
Which enzyme is the committed step in glycolysis
Phosphofructokinase 1
Step 4 enzyme
Aldolase
What happens in step 4 glycolysis
-The hexose is split to form two trioses.
-C1 - C3 of fructose 1,6-bisphosphate -> Dihydroxyacetone phosphate.
-C4 - C6 of fructose 1,6-bisphosphate -> Glyceraldehyde 3-phosphate.
What are you left with after step 4 glycolysis
Dihydroxyacetone phosphate and glyceraldehyde 3-phosphate
Enzyme 5 glycolysis
Triose phosphate isomerase
What happens step 5 glycolysis
Isomerisation of dihydroxyacetone phosphate to Glyceraldehyde 3-phosphate by triose phosphate isomerase
(maintains steady state - G3P)
