Hey, everyone. So remember glycolysis is a sequence of 10 biochemical reactions split between phases A and B phase A recall is the energy consuming phase. Phase B is the energy producing phase. All right. Now, for phase A, we're gonna have consisting of its first five reactions. It results in the conversion of one glucose into two glycerol I three phosphate molecules which re abbreviate as G three P. Now reactions one and three are irreversible and each consumes one A TP. If we take a look here we have glucose, we have to consume one A TP in order to add a phosphate group to our glucose, transforming it into glucose six phosphate. This can deny summarize into fructose six phosphate. This reaction two is reversible. Next, we need to add another phosphate group. So that means another A TP has to be consumed. Doing this as our second inorganic phosphate transforming fructose six phosphate into fructose, 16 bisphosphate bis, meaning two phosphate groups. From here we go into reaction four which can split into two different ways. We could create uh dihydroxy acetone phosphate. Or here we can make two glyceraldehyde three phosphates. And here reaction five, they can go between each other. It's a reversible reaction. Now, this encompasses our phase a of glycolysis. What's in blue would be our phase B which we'll talk about later on. For. Now, let's just continue to talk about these different reactions in phase a of glycolysis.
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Glycolysis Concept 2
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In this video, we're gonna take a look at reactions one and two of phase a of glycolysis. Now reaction one is phosphorylation here, the enzyme hexokinase catalyzes the phosphorylation of glucose. Here it uses a TP as a source of energy and phosphate. Now remember that a kinase is an enzyme that transfers a phosphate group from a TP to some specified molecule. We have glucose. We're using our hexokinase. It's gonna transfer a phosphate group from A TP, transforming it into AD P and then the h that was part of glucose here is transformed into a phosphate group in the form of po 32 minus. So, in that way, we go from glucose to glucose six phosphate. Now, here reaction two is a summarization. The enzyme of phospho glu glucose isomerase is summarizes glucose six phosphate to fructose six phosphate. They're just isomers of each other. So here if we take a look, the number of carbons, hydrogens, oxygens and phosphates remain the same. So we just have the changing of glucose six phosphate to fructose six phosphate through an isomerase. So remember an isomerase is just a way of going between this different isomer forms the same molecular formula overall, which is different connections, right. So that represents reactions one and two of phase a of glycolysis.
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Glycolysis Concept 3
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In this video, we're gonna take a look at reaction three a phase a of glycolysis. Now like reaction one reaction three also consumes an A TP molecule. That's because reaction three is also phosphorylation here. Though we're dealing with our substrate in the form of fructose six phosphate initially instead of glucose. And because of that, our enzymes gonna be slightly different here for reaction three. The enzyme we're using is phospho fruct kits. So it's still a kinase. So it's still being utilized to transfer a phosphate group from a TP to our fructose six phosphate molecule. Right. So it's gonna catalyze the phosphorylation of fructose six phosphate again, because it's a kinase, it uses a TP as a source of energy and a phosphate group. So here we have our fructose six phosphate and it's this hydrogen in question, that's going to be replaced by a phosphate group. Again, we're utilizing our phosphofructokinase to do it. And now we're gonna have our po 32 minus here as well. And in that way, we just created fructose 16 bisphosphate for reaction three of phase a of glycolysis
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Glycolysis Example 1
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Which of the following statements is incorrect about a TP and glycolysis reactions. One and three, right. A TPP provides the inorganic phosphate or phosphorylation reactions. This is true. Remember, both of these steps are irreversible. Both of them consume an A TP molecule so that we can do phosphorylation hydrolysis of the high energy po bond phosphorus oxygen bond in A TP provides energy to carry out phosphorylation. Yes, that is true. Remember, hydrolysis is one of those types of biochemical reactions that helps to produce energy. Here we're using hydrolysis to cut that high energy bond in order to provide energy necessary for phosphorylation energy produced in reactions. One and three is used to synthesize a TP from AD P. No, this is incorrect. Remember we're using an A TP molecule in reactions one and three, we are going to use a kinase to transfer phosphate group from these A TP to their specified molecules. In turn, that changes A TP into AD P. So C is incorrect. Now here, Kinas and reactions one and three use a TP as the co enzyme. That is true. They are using a TP as a coenzyme. Remember kinas again are just enzymes are utilizing to transfer a phosphate group from the A TP to our specified molecule. In this case, the A TP is needed for these irreversible reactions and they serve as co enzymes. So here, this is true. The only statement that's provided here that's incorrect would be option C.
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Glycolysis Concept 4
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Now, in reaction for a phase of glycolysis, we say the enzyme aldolase cleans the middle carbon carbon bond of the fructose ring. And we're gonna say this results in the formation of two trios phosphates. So here we have our fructose, 16 bisphosphate. We utilize all the las as our enzyme. It's gonna cut here. So it cuts right in the middle, that's gonna create our two trials phosphates. So here we're making dihydroxy acetone phosphate. And then here we're making glyceraldehyde three phosphate. So these would be the two molecules that we're creating from our fructose, 16 bisphosphate.
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Glycolysis Concept 5
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Now reaction five of phase a of glycolysis represents the final reaction for phase a of glycolysis in it, it represents a isomerization reaction. So here we're gonna say dihydroxy acetone phosphate, which we abbreviate as DH A P is, is summarized to glyceraldehyde three phosphate which we abbreviate as G three P. Now this is catalyzed by the enzyme trichy phosphate. And because we're dealing with isomerization, it would be an isomerase. So if we take a look here, we have dihydroxyacetone phosphate that I summarizes into Glycerol high three phosphate. Since it's a reversible reaction, it can go the opposite way as well. Or we're going from G three P to DH A P. Now here, dihydroxy acetone phosphate, acetone ketone, which will mean that this carbon in the middle would have to be a ketone carbon. And then here, glyceraldehyde aldehyde is in the name, remember an aldehyde is a carbon group. So C double Bondo and connected to an H. So this is how we're going between these two different molecules because it's an isomerization reaction. We use an isomerase to do it. Remember this represents the final reaction reaction five of phase a of our glycolysis.
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Glycolysis Example 2
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Which one of the following statements is incorrect about glycolysis phase A. All right. So, phosphorylation reactions, one and three are catalyzed by Kinas. This is true. Kinas are the enzyme that we use for the transferring of a phosphate group from a TP to our specified molecule bond cleavage. In reaction four produces a TP. No. Remember phase A deals with the consumption of energy, not the production of energy. And then here, if we're talking about bond cleavage, we're really should be talking about hydrolysis. Hydrolysis is what can lead to the production of energy, but that's not what's happening here. So this is incorrect bole in a reaction. Four produces two trials phosphates. This is true. We create dihydroxy acetone phosphate and glyceraldehyde three phosphate which can I summarize between each other isomerization of DH A P, which is our dihydroxy acetone phosphate and G three P, which is our glyceraldehyde three phosphate is catalyzed by tral phosphate isomerase. Now here this is a isomerization reaction. So the enzyme of choice would have to be and isomerate. This is a true statement. So, out of our choices, the only one that's incorrect would have to be option B.
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Problem
Problem
Classify each one of the following reactions as phosphorylation (P), isomerization (I), or neither (N).
a) ____ Conversion of glucose into glucose-6-phosphate.
b) ____ Conversion of glucose-6-phosphate into fructose-6-phosphate.
c) ____ Conversion of DHAP into G3P.
d) ____ Cleavage of fructose-1,6-bisphosphate into DHAP and G3P.
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Problem
Problem
Which one of the following compound pairs is produced by cleavage of fructose-1,6-bisphosphate?
A
Dihydroxyacetone phosphate and glyceraldehyde-3-phosphate
B
Glyceraldehyde-3-phosphate and glyceraldehyde-2-phosphate
C
Glyceraldehyde-3-phosphate and CO2
D
Dihydroxyacetone phosphate and 3-phosphoglycerate
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Glycolysis Concept 6
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We now take a look at phase B of glycolysis. Now, phase B of glycolysis consists of its last five reactions. Now converts two G three PS or Glycerol I three phosphates into two pyros and extracts energy in the process. Here is going to produce two N A DH s and four A TP molecules. We also say that reaction 10, the last reaction of phase B is irreversible. So we've gone through phase A all here and red, which leads us into the blue portion which is phase B. So here we have our inorganic phosphate being incorporated to create 13 bis phospho glycate. And we have the production of N A DH as a pro in a process. So we created a high energy molecule in the form of N A DH. We then have a reversible reaction seven where our 13 bis phospho glycate changes into three phospho glycate. We've lost a phosphate group so that we can give it to AD P to convert it into a TP. So we've just created a TP in reaction eight, we've removed yet. Well, we've switched the position of our phosphate group. I removed it entirely to transform three phospho glycate into two phospho glycate. Then through the use of the loss of water reaction. Nine, we have the creation of phosphoenolpyruvate. Now we'll go in depth in terms of each of these. We'll learn steps to help us memorize the different things that are being produced and in which steps. So I know it's a lot. So don't feel overwhelmed because it is quite a lot of reactions. But we're gonna learn summaries on how to basically remember this mass amount of information. And then finally, here we have the removal of the last inorganic phosphate and the creation of A TP again to give us at the end, pyro. Now remember we have two G three P molecules. So this happens twice. So here we're making one N A DH and then two A TP. And it does it again to give us another N A DH and two more A TP. So that's how we come up with a total of two N A DH s and four A TP molecules from phase B of glycolysis, right? So this just gives us an overall view of what's happening within this phase of glycolysis. And we're about to go more in depth with each one of these reactions.
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Glycolysis Concept 7
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So here we take a look at reaction six of glycolysis. It happens twice because we have two G three P molecules that can be oxidized. Here, they undergo oxidation to produce 13 bis phospho glycerine, which are gonna abbreviated as 13 BPG. Now, here it's catalyzed by the enzyme glyceraldehyde three phosphate. And remember our class of enzymes that we use for oxidation reactions will be dehydrogenase. So this would be ad hydrogen in this reaction because it's an oxidation N any positive is gonna be reduced to N A DH. So here we have our Glycerol high three phosphate and we're gonna say with the incorporation of an inorganic phosphate and the reduction of N ad positive to N A DH through the utilization of our enzyme glyceraldehyde three phosphate dehydrogenase, we create 13 bis phospho glycate. So here what happens is this h is transformed into opo three to minus. And what we need to see here is that this 13 bis phospho glycate is basically going to be our molecule that eventually we want to convert into pyruvate. So this is what we need to get to at the end. This pyruvate at the end of our glycolysis, right. So just remember step six or reaction six happens twice because we have two G three molecules that need to be oxidized. Oxidation are a class of enzymes that we utilize are our dehydrogenase. The name of the enzyme is just the substrate name followed by dehydrogenase.
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Glycolysis Concept 8
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Now reaction seven deals with a phosphate transfer. Again happens twice. Here we have 13 bis phospho glycate which is B 13 BPG. It produces three phospho glycate three PG by losing an inorganic phosphate group. Now this is catalyzed by the enzyme phosphor glycate kinase. Remember a kinase deals with the transferring of a phosphate group. In this case though it transfers a phosphate group to ad P transforming it into a TP. So here we just created some energy. So as we can see, 13 bis phospho glycate, it has two our of our phosphate groups. But through the utilization of our kinase, we lose one of these inorganic phosphates. So now we just have a negative oxygen here that phosphate group that was lost again, goes to ad P transforming it into a TP. So this is what reaction seven of phase B of glycolysis represents.
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Glycolysis Concept 9
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Reaction eight is in a summarization reaction that happens twice. We have three phospho glycerated. So we have really two of them of three pg. So that's why it happens twice. It undergoes a summarization to yield two phosphate glycate which is two pg. Now this is catalyzed by the enzyme phospho glycate muta. Now muta is just a class of isomerase. Remember isomers same molecular formula, different connections. The muta here helps the movement of our phosphate group or inorganic phosphate group from position three carbon three to position two. OK. So what we have here is that this group here is getting moved to here and we're gonna say that we're gonna make our two phosphor glycate. So the oh comes here. So we just have the movement of these functional groups within our three phospho glycerated to create two phospho glycate. The the inorganic phosphor was connected this to this oxygen which is on position three carbon three. But now it's being moved over to this position which is part of carbon two. Now this, as you can see is a reversible reaction. So although we're moving this around, we can go backwards in terms of this reaction if necessary. Again, a muta is just a class of, is summaries.
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Glycolysis Example 3
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Here, it says which of the following glycolysis reactions will produce an A TP molecule. Here, we're going from three fossil glycerine to two fossil glycerine here. This represents an isomerization reaction where we utilize a class of isomer ases called muta. We're just moving the inorganic phosphate from one position on three fossil glycate to another position to transform it into two fossil glycerine. This does not produce a TP, glyceraldehyde three phosphate, 213 bis phospho glycerine. Now, this represents an oxidation reaction. We have the incorporation of an inorganic phosphate group and we are producing N A DH because we are reducing N ad positive. Although we're making a high energy molecule in the form of N A DH, we do not make a TP glucose to glucose, six phosphate. Now, this reaction is part of phase a of glycolysis and it is an energy consuming process. We need to basically invest a TP in order to add that phosphate group to glucose. So this is gonna do the opposite. It's not gonna produce a TP, it's going to consume it. So by process of elimination, it's D here we have 13 bis phospho glycate and we're going to three phospho glycate. We're gonna say that in this reaction, we're utilizing a kinase. And with this kinase, we're gonna lose an inorganic phosphate from 13 bis phospho glycate. And we're gonna give it to ad P transforming it into a TP. In that way we're making or producing an A TP molecule.
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Glycolysis Concept 10
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Now, reaction nine of glycolysis represents a reversible dehydration reaction. Here, it happens twice and we have two phospho glycate which is two PG, it undergoes dehydration to produce phospho eop pru or pe p. Now, here it's catalyzed by the enzyme enolase. So, here we're going to say that we have our two phospho glycate, we're gonna use our enolase and in the process, we're gonna lose water. So we lose H2O. Now, here we lose this hydrogen and this oh carbon still need to maintain their four bonds because their tetra valent, they wanna make four bonds. So they have no other options but to make a double bond with each other, this transforms our two fossil gly gly glycate to fossil ennore. Right? So, again, reaction nine of glycolysis represents a reversible dehydration reaction. And we're utilizing the enzyme enolase in order to do this
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Glycolysis Concept 11
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Now, reaction 10 represents a phosphate transfer. It also represents the last step in glycolysis and it's also irreversible. Now, here pep yields pyruvate by losing its inorganic phosphate group. We're gonna say that this is catalyzed by the enzyme pyruvate kinase. Again, we know it's a kinase because we have a phosphate group being transferred. Now, the ad P gains the inorganic phosphate group to produce a TP. So here we have our phospho eop pyruvate molecule. We use our pyruvate kinase enzyme which helps us to transfer our inorganic phosphate to ad P to change it into a TP. Now, here by doing this, we form our pyruvate molecule which has a carbonyl now where the inorganic phosphate group used to be. And this ch two group is converted into a methyl group. And this is how we get our pyruvate molecule. This pyruvate molecule represents the final molecule within this glycolysis reaction. So we've gone through phase A and phase B for a total of 10 reactions to get to this final molecule
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Glycolysis Example 4
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Which of the following enzyme catalyzes the conversion of phospho ENYT to pyruvate. Now, this represents reaction 10 of glycolysis, which is a phosphate transfer reaction. We know that when we're transferring phosphate groups, that involves our class of enzymes known as Kinas. So if we take a look, we have a kinase here and we have a kinase here. This couldn't be the answer. However, dehydrogenase because that deals more with oxidation, not the transferring of a phosphate group and then pyruvate carboxylate. That's just talking about our pyruvate group with a carbo carbolic acid group that's been dep proton. It has an O negative. And remember we're looking for the enzyme and it doesn't end with the name of an enzyme as well. Now, here it's either C or D now phospho eop pyruvic carb carboxy kinase. This deals with the carboxyl of PEP. But remember we're not trying to add a Carboy acid group to PEP. We're trying to lose a phosphate group from PEP in order to change it into pyruvate. This happens not with option C as an enzyme, but with option D pyruvate kinase is the enzyme of choice which will lead to the transferring of our phosphate group from PEP to AD P, transforming it into a TP. While doing this, PEP is transformed into pyruvate. So option D would be our final answer.
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Problem
Problem
Which enzyme catalyzes the oxidation of glyceraldehyde-3-phosphate in reaction 6 of glycolysis?
A
glyceraldehyde-3-phosphate dehydrogenase
B
glyceraldehyde-3-phosphate acyltransferase
C
glyceraldehyde-3-phosphate oxidase
D
triosephosphate isomerase
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Problem
Problem
What is the energy output of reaction 7 of glycolysis (1,3-bisphosphoglycerate to 3-phosphoglycerate)?
A
2 ATP
B
2 NADH
C
1 ATP
D
1 NADH and 1 FADH2
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Problem
Problem
What product is formed when phosphoglycerate mutase moves the phosphate group in 3-phosphoglycerate?