Carbohydrate metabolism Flashcards
Major source of energy in the body
Glucose
Other name of Glycolysis
Embden Meyerhof
Where does glycolysis occurs? (Found in)
Cytosol
2 types of glycolysis
Aerobic
Anaerobic
Occurs in the presence of oxygen
Aerobic
Absence or low oxygen tension
Anaerobic
Phase: Step 1 to step 5
Preparatory phase
ATP is invested / expended / used
Preparatory phase
ATP is synthesized : step 6-10
Pay-off phase
Cannot go glycolysis directly
Trap the glucose
Step 1: Phosphorylation of glucose
Step 1:
Enzyme:
Phosphorylation of Glucose
Hexokinase
Glucokinase
Irreversible
Why does glycolysis cannot go directly in step1?
Because glucose can easily be diffused in the blood
To trap the glucose it must undergo?
Phosphorylation
Used when glycolysis occurs in the liver Low affinity to glucose Not inhibited by its product Active after meals Large KM
Glucokinase
Occurs in the other organs of the body / muscle cells / other tissues
Higher affinity to glucose
INHIBITED by its product
Small KM
Hexokinase
Product of Glucokinase
Glucose 6 phosphate
Step 2:
Enzyme:
Conversion of Glucose 6-phosphate to Fructose 6-phosphate
Phosphohexose isomerase
Reversible
Common of step 1 and 3
Both has Magnesium and ATP
Repel the negative charges of the phosphate group
Magnesium
Conversion of pyran to furan
Split the glucose
Step 2: Conversion of glucose 6-phosphate to Fructose 6-phosphate
Step 3:
Enzyme:
Phosphorylation of Fructose 6-phosphate to Fructose 1-6, Biphosphate
Phosphofructokinase 1
Irreversible (2nd)
Important player in glycolysis
Catalyzes committed step
Phosphofrutokinase 1 (PFK 1)
Step 4:
Enzyme:
Cleavage of Fructose 1,6-Biphosphate
Aldolase
How many carbons in fructose 1,6 Biphosphate?
6 carbons
Breaking / splitting 6 carbon to 3 carbon
Step 4: cleavage of fructose 1,6- Biphosphate