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. within no time they came closer and before George could run for his
life one of these men abruptly grasped the
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. He tried to punch them with his left hand but was
quickly overpowered by one of these men he then changed the George left hand as
well
one of those men then quickly picked up an old rusty chainsaw stained with blood
he used this chainsaw to cut the Geroge's body into two halves. George's muffled whales
in agony were enough to disrupt the quietude of the forest. One of these
devilish thoughts magically transformed the left half of George's corpse into right half.
The same George who was happily rambling in the forest a few moment
back was now lying on the same land divided into two congruent blood-stained
parts. now I will remove one of these part as whatever happens to this part,
the same thing will happen on that part as well. One of those the lust rascals
searched the pocket of the corpse and found a bank cheque which he stole. He
also attached a special chain onto it. The chain had special magnetic capabilities
that it could pull a coin that once the George had owned. The next Robber came
forward and removed the chain in order to obtain that coin
Poor George’s corpse was now left with a chain attached on its right side
another fussy robber then shifted the chain to the center of the body. Their
story of lust does not end here. One of them then squeeze the dead body. Now that
energy was concentrated to this central chain, a robber came forward to remove
the chain thus obtaining the energy in the form of a coin
in the end we are left with two squeezed halves of the body with two coins and a
bank cheque from each half. So what this story has to do with glycolysis let me
tell you. In this story, in this analogy the forest is actually the cytosol of
cell in which these reactions of glycolysis occur
and this man George is actually a six-carboned sugar called glucose. In first
step this robber or enzyme attaches a phosphate to the right hand of George
so energy as well as the chain, the phosphate is obtained by breaking down
ATP and thus the glucose with phosphate attached to its six carbon so we form
glucose 6-phosphate and the enzyme which has kinase activity for glucose it is
called glucokinase as well as it has an other form called hexokinase. In second
step what happens that the robber put a mask on the George so this is like
converting the glucose 6-phosphate into its isomeric form into its
isomer so the enzyme which is involved is isomerase and we call this enzyme is
acting on phosphoglucose we call it phosphoglucose isomerase. In third
reaction the chain the phosphate is also tied to the other half, of course ATP is
being utilized in this process and enzyme which has kinase activity for
phosphofructose it is called phosphofructokinase 1 and the substance, the product
which is formed which is having phosphate at carbon number one 0:05:16.669,0:05:21.650 as well as at carbon number six this is called fructose 1 6
bisphosphate.
In this reaction robber cuts the George into two parts with a chainsaw.
So this is just like cutting the fructose 1 6
bisphosphate from the center and the enzyme which is required is called
aldolase. So we obtain two products one is dihydroxyacetone phosphate which is
having phosphate at carbon number 1, so this is dihydroxyacetone phosphate.
And the other product, which we obtain is having the phosphate attached to its
carbon number 3 so with this is called glyceraldehyde 3-phosphate
glyceraldehyde 3-phosphate.
In this reaction, a robber magically convert this part into this one so that
it means that it converts that dihydroxyacetone phosphate into
glyceraldehyde 3-phosphate.
So because glyceraldehyde-3-phosphate and dihydroxyacetone phosphate are
isomers of each other so this enzyme which interconvert them
through a reversible reaction is called isomerase. So now we have two molecules
of glyceraldehyde 3-phosphate from now
on I will only discuss the reactions which occurs with this glyceraldehyde
3 phosphate and of course you must understand that whatever reaction
that happens with this glyceraldehyde 3-phosphate the same events
also occurs with this glyceraldehyde-3-phosphate. So in next
reaction, what happens that one of the robbers it
will come forward and it will search the pocket of this
George dead body and it will attach a chain, a special chain onto
it. So the check why I am calling it check because some hydrogen is removed
from glyceraldehyde 3-phosphate. From the functional group of glyceraldehyde
3-phosphate hydrogen is removed and this hydrogen is added to NAD+ to form NADH
So what we get? The bank cheque, NADH, as well as 1 3 bisphosphoglycerate.
I am calling it 1 3 bisphosphoglycerate I am not calling it 1 3
bisphosphoglyceraldehyde because hydrogen is removed from its functional
group. It is no more glyceraldehyde it is now glycerate because it is no more
aldehyde its hydrogen is removed so we obtain 1 3 bisphosphoglycerate as well
as NADH in this process and the enzyme which removes the hydrogen from which
removes the hydrogen atom from glyceraldehyde 3-phosphate this enzyme
is called glyceraldehyde 3-phosphate dehydrogenase and of course it is also
attaching a phosphate chain onto carbon number 1 and this phosphate chain
because it is a dead body, energy is not utilized in this process in the form of
ATP, it uses the inorganic phosphate it uses the phosphate from inorganic
phosphate to be attached here. no ATP is being used in this process. In next
reaction what happens is that this chain is removed so when this chain is removed we
get a coin what is the coin? Coin is the energy
currency, that is we obtain ATP. So now from 1 3 bisphosphoglycerate, phosphate is
being removed from carbon it's number 1 and of course ATP is obtained so the product
which is formed is 3 phosphoglycerate and the enzyme is phosphoglycerate
kinase so next a fussy robber shifts the position of phosphate to the center
of body this robber mutates the position of phosphate so from 3 phosphate from
carbon number 3 the phosphate is shifted to, phosphate is mutated to carbon number
2 so the enzyme which mutates the position of phosphate this is called
phosphoglycerate mutase and because it is acting on
phosphoglycerate we call it phosphoglycerate mutase and this is a
reversible reaction now a robber picks up the this part of dead
body and squeezes it so we get phosphoenolpyruvate as well as some
water molecules and the energy is now concentrated into this central phosphate
chain and the enzyme is Enolase. You can remember this phosphoenolpyruvate or PEP.
you can remember this PEP by correlating it with a bottle of Pepsi Cola. So just
remember that we obtain a bottle full of water
so phosphoenolpyruvate is formed as well as some water is obtained and of course
the energy is concentrated into this central phosphate Chain. In last reaction
a robber will come forward to remove this phosphate chain thus obtaining a coin
from this dead part of the george
so enzyme is pyruvate kinase and what we obtained, pyruvate as
well as an ATP molecule. This is the summary of all the steps of glycolysis
now from here, from the starting up to here you can see that
we are not getting any energy in the form of ATP rather we are investing the
energy in the form of ATP. So this is the energy investment
phase and from here onward we are getting the energy in the form of ATP as
well as NADH in the form of ATP as well as NADH. so this is
the energy payoff phase. This is just like doing a business that in the
business in doing the business first we invest the money and then there is, after
some time we get the money back, the money is paid off in the form of
profit so of course from this glyceraldehyde 3-phosphate
the similar reactions also happens with this glyceraldehyde 3-phosphate
so ultimately we obtain 1 2 3 & 4 so ultimately we obtain 4 ATP molecules
directly and we obtain 2 NADH but 2 ATP molecules are also utilized during this
process so how many net ATP we directly obtain? total 4 ATP and out of these 4
ATP molecules 2 are utilized so net ATP which we obtain directly are 2 ATP
molecules and of course we are also getting 2 NADH molecules and
from each NADH molecules we obtain three
ATP molecules so 2 multiplied by 3 is equal to 6 so total how many ATP
molecules, net how many ATP molecules we are getting 6 plus 2 is equal to 8 so
net we are getting 8 ATP molecules in the process of glycolysis. So this
is how you can memorize the glycolysis with the help of a simple visual story, a
horror story. I hope you like this video if so please press the thumbs up button
and please do consider subscribing my channel and press the bell icon thank
you for watching