- Cell junctions are the connection between cells.
- Cell junctions are a class of cellular structures consisting of multiprotein complexes that provide contact between a cell and an extracellular matrix.
- After the name of three German scientists- Embden, Meyerhof and Parnas it is known as EMP pathway.
- It is the principal rout for catabolism of glucose, fructose, galactose and other carbohydrates.
- It degrades glucose to generate ATP.
- Glycolytic pathway can broadly divide into two phase
- Preparatory phase:- This phase require energy in the form of ATP.
- Energy yielding phase:- In this phase energy is generated in the form of ATP.
Energetics of glycolysis
The number of ATP generated per molecule of glucose varies , depending upon the condition.
Total number of ATP used is 2 and total number of energy yield is 10. So the net ATP is 8.
Regulation of glycolysis
There are three irreversible steps which are catalyzed by hexokinase,phosphophructo
Kinase and pyruvate kinase.
These are the site of regulation of glycolysis.
The enzyme Hexokinase , Glucokinase , phosphofructokinase , pyruvate kinase activated
by hormone Insulin, AMP , NAD and inhibited by Glucagon, ATP, Citrate.
Fluoride is the inhibitor of Enolase , Arsenic is the inhibitors of pyruvate dehydrogenase.
Fate of pyruvic acid
- Pyruvic acid is the key product of glycolysis
- There are three major ways to which different cell handle pyruvic acid.
- These are acid fermentation, Alcoholic fermentation , aerobic respiration.
Lactic acid fermentation- It is occur in lactic acid bacteria. During exercise when oxygen in unavailable for respiration muscle cell use lactate dehydrogenase to transfer hydrogen atom from NADH to pyruvic acid.
Alcoholic fermentation- When oxygen is limiting yeast carryout conversion of pyruvate to ethanol.
Importance of fermentation:-
- It recycles NAD+ which is an electron acceptor required for glycolysis to proceed.
- It is important for commercial production of alcohol, organic acids and antibiotics.
