Glycolysis
Dr. Aizaz 
GLYCOLYSIS
Glycolysis means breakdown of glucose in order to get energy.
Forget about glycolysis and let me tell you a story;
George was strolling alone through the darkening passageway of that forest after a long tiring day when he felt some masked faces hurriedly approaching towards him.
607157061c757_lg.png)
Within in no time they came closer. Before George could run for his life, one of those men abruptly grasped George’s right hand and put a special chain onto it. A mask was put on his face as he tried to yell out loudly.
60718348f1ef8_lg.png)
He tried to punch them with his left hand but was quickly overpowered by one of those men. He then chained George’s left hand as well.
607184ac6dbe7_lg.png)
One of those men then picked up an old rusty chainsaw, stained with blood. He used this chainsaw to cut the George’s body into two halves.
607185e223df9_lg.png)
George’s muffled wails in agony were enough to disrupt the quietude of the forest.
One of those devilish thugs magically transformed the left half of George’s corpse into right half.
6071853fd5e96_lg.png)
The same George who was happily rambling in the forest a few moments back, was now lying on the same land, divided into two congruent, blood-stained parts.
One of these lusty rascals then searched the pocket of the corpse and found a bank cheque, which he stole. He also attached a special chain onto left side of the corpse’s half.
6071869da8e1d_lg.png)
This chain had special magnetic capabilities such that it could pull a coin that George had owned. The next robber then removed the chain in order to obtain the coin.
60718720b6a47_lg.png)
Poor George’s corpse was now left with a chain attached on its right side. Another fussy robber then shifted the chain to center of the body.
607187e391193_lg.png)
Their story of lust doesn’t end here. One of them then squeezed the dead body. Now that energy was concentrated into this central chain.
6071887469d7d_lg.png)
A robber came forward to remove this chain thus obtaining the energy in the form of a coin.
The forest is cytosol and the man is six-carboned sugar; Glucose.
During first reaction. Glucose is attached with a phosphate chain on sixth carbon (the left hand of man in this anaology), Thus forming glucose 6 phosphate. The Robber, I mean enzyme is Hexokinase or Glucokinase. The robber overpowers the man (glucose) by using energy. (meaning that energy from ATP is used).
6071893fbab1d_lg.png)
The second reaction involves converting the glucose 6 phosphate into its isomer Fructose 6 phosphate. Enzyme (or robber) is called Isomerase.
60718c4e38819_lg.png)
Next, the other end of glucose i.e. Carbon number one is also attached with a phosphate group (Left hand of the man is also tied with the chain). Now it becomes Fructose 1, 6 Bisphosphate. Enzyme or robber is having kinase activity on PhosphoFructose and thus called Phosphofructokinase. Energy is used to tie this chain (so one ATP is used)
60718c977085a_lg.png)
Uptill no energy is obtained from this process. Rather energy is being utilized in the form of ATP. These above-mentioned reactions constitute energy investment phase of glycolysis. Next we are going to study energy harvesting or payoff phase in which we will obtain energy.
Thus, is just like a business. First we invest the money and then there is payoff phase.
Now, the Fructose 1, 6 Bisphosphate is cut into two with the help of aldolase enzyme. Now we obtain two pieces of the body of fructose 1, 6 bisphosphate. One piece is called DHAP (Dihydroxy Acteone Phosphate) and Other piece is Glyceraldehyde 3 phosphate.
6071a79115380_lg.png)
DHAP is also converted to glyceraldehyde 3 phosphate by the enzyme isomerase.
6071a7f17c4a5_lg.png)
Another chain is attached to the one end of Glyceraldehyde 3 Phosphate, Since it’s dead now, No energy from ATP is used, Rather inorganic phosphate is used as a source of phosphate group. At the same time, Bank cheque in the form of NADH is obtained. Enzyme removes Hydrogen from Glyceraldehyde 3 phosphate in order to attach with NAD to form NADH. This Hydrogen removing enzyme is called Glyceraldehyde 3 Phosphate DeHydorgenase. The product that is formed now has Phosphate at both ends and is called 1, 3 Bisphosphoglycerate.
6071a88f200dd_lg.png)
The newly attached chain with special properties to the fetch the money is then removed to form an ATP molecule. Resultingly 3 Phophoglycerate is formed and enzyme is phosphoglycerate kinase (named so because of ability to catalyzed backward reaction).
6071a8ec33d79_lg.png)
Phosphate chain is then shifted to the center (carbon no 2). Mutase enzyme is used. And 2 Phosphoglycerate is formed.
6071a94a5909a_lg.png)
Then this 2-Phosphoglycerate is squeezed, water is released, and Phosphoenolpyruvate is formed. Enzyme is Enolase and the product that is formed is called PhosphoEnolPyruvate.
6071a99b14af0_lg.png)
As it is squeezed energy is conentrated to the center. And Finally, this chain is removed in order to obtain ATP. This results in formation of Pyruvate. Enzyme is Pyruvate kinase .
6071a9fee4cb4_lg.png)
Summary
6071aee0b1dff_lg.png "Glycolysis")