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So these tiny molecules shown here are basically our surfactant molecules. So we have the non polar hydrophobic tail and the polar hydrophilic head. So in the same way that we discussed here, the head of the surfactant, the head of the surfactant basically interacts with the surface of our fluid, but the tail points away towards our air found within this cavity. So the wall of the alveolus is lined with the polar fluid that contains a high surface tension. This means that because of the high surface tension, we require a relatively high pressure to expand and inflate those balloon like structures when we basically inhale our air. Now, by mixing the surfactant into that fluid, and by the way, the surfactant is produced by specialized type of cell inside the lungs known as the alveolar type two cells. | Surfactant in Alveoli and Surface Tension.txt |
So the wall of the alveolus is lined with the polar fluid that contains a high surface tension. This means that because of the high surface tension, we require a relatively high pressure to expand and inflate those balloon like structures when we basically inhale our air. Now, by mixing the surfactant into that fluid, and by the way, the surfactant is produced by specialized type of cell inside the lungs known as the alveolar type two cells. By mixing the surfactant, which is our detergent with the fluid, we decrease the surface tension as a result of what we discussed earlier. And by decreasing the surface tension, we make it much easier for ourselves to actually inflate those alveoli. So we decrease the pressure that is needed to expand the alveoli during the process of inhalation. | Surfactant in Alveoli and Surface Tension.txt |
Let's begin with the same exact spermatogonium, the same exact precursor cell. Once again, we're not considering the autosomes. We're only looking at the sex chromosome. So we have replication taking place. We produce these two identical cystochromatids. These two? | Aneuploidy and Nondisjunction (Part II) .txt |
So we have replication taking place. We produce these two identical cystochromatids. These two? Identical cystochromatids and let's assume that nondisjunction does not take place during my Ptosis during meiosis one so during meiosis one, we have the normal segregation process taking place so these fibers are able to extend they form connections with these chromosome pairs and they move apart to form the following two cells. So cell number one and cell number two that are normal now in anaphase of meiosis two. So anaphase two of meiosis. | Aneuploidy and Nondisjunction (Part II) .txt |
Identical cystochromatids and let's assume that nondisjunction does not take place during my Ptosis during meiosis one so during meiosis one, we have the normal segregation process taking place so these fibers are able to extend they form connections with these chromosome pairs and they move apart to form the following two cells. So cell number one and cell number two that are normal now in anaphase of meiosis two. So anaphase two of meiosis. Now, we have nondisjunction take. Place in both of these cells. Now, of course, we can have nondisjunction taking place in one of these two cells, but let's assume that nondisjunction takes place in both of these cells. | Aneuploidy and Nondisjunction (Part II) .txt |
Now, we have nondisjunction take. Place in both of these cells. Now, of course, we can have nondisjunction taking place in one of these two cells, but let's assume that nondisjunction takes place in both of these cells. What will happen is so we have one fiber forms a connection, the other one doesn't. One fiber forms a connection, the other one doesn't. And so when we have the segregation process take place, this entire pair of cystochromatids moves to one cell. | Aneuploidy and Nondisjunction (Part II) .txt |
What will happen is so we have one fiber forms a connection, the other one doesn't. One fiber forms a connection, the other one doesn't. And so when we have the segregation process take place, this entire pair of cystochromatids moves to one cell. So we form. Sperm cell number one. The other one doesn't get anything. | Aneuploidy and Nondisjunction (Part II) .txt |
So we form. Sperm cell number one. The other one doesn't get anything. So we form sperm cell number two and the same thing happens here. This entire pair of identical cytochromatids moves into sperm cell number one. And the other one basically gets nothing. | Aneuploidy and Nondisjunction (Part II) .txt |
So we form sperm cell number two and the same thing happens here. This entire pair of identical cytochromatids moves into sperm cell number one. And the other one basically gets nothing. So just like in this case, we have sperm cell two and sperm cell four that have nothing but sperm cell one, in this case contains two identical X chromosomes. In here, we have two identical Y chromosomes. And so now, if we study the same exact picture as we discussed in this particular diagram, if we take, let's say, sperm cell number one and we combine it with a normal X cell, what we're going to get? | Aneuploidy and Nondisjunction (Part II) .txt |
So just like in this case, we have sperm cell two and sperm cell four that have nothing but sperm cell one, in this case contains two identical X chromosomes. In here, we have two identical Y chromosomes. And so now, if we study the same exact picture as we discussed in this particular diagram, if we take, let's say, sperm cell number one and we combine it with a normal X cell, what we're going to get? Is an individual that has three X chromosomes. So this will be replaced with an X chromosome. We combine and so we'll form a Zygote that has anapply that will contain axxx genotype arrangement. | Aneuploidy and Nondisjunction (Part II) .txt |
Is an individual that has three X chromosomes. So this will be replaced with an X chromosome. We combine and so we'll form a Zygote that has anapply that will contain axxx genotype arrangement. So an X and X and an X. Likewise, if we take this sperm cell and combine it with the normal XL, we're going to have an arrangement of XYY. And finally, if either one of these two sperm cells for or combines with a normal xcel, we're going to have an EXO condition, just like we had in this particular case. | Aneuploidy and Nondisjunction (Part II) .txt |
So an X and X and an X. Likewise, if we take this sperm cell and combine it with the normal XL, we're going to have an arrangement of XYY. And finally, if either one of these two sperm cells for or combines with a normal xcel, we're going to have an EXO condition, just like we had in this particular case. And once again, and I have to emphasize this, Meiosis, one or two can experience nondisjunction. So we have two places where nondisjunction can. Take place in Meiosis. | Aneuploidy and Nondisjunction (Part II) .txt |
And seven of these 20 different amino acids have readily ionizable side chain groups. And what that means is the side chains can basically lose or gain an age atom at a specific PH value. And so for a specific amino acid that is ionizable at certain PH values, the side chain will have a charge. But at other PH values, the side chain will be neutral. Now, to see exactly what we mean by this, let's take a look at the following two examples. So these are the two out of the seven ionizable amino acids. | Isoelectric Focusing and Isoelectric Point .txt |
But at other PH values, the side chain will be neutral. Now, to see exactly what we mean by this, let's take a look at the following two examples. So these are the two out of the seven ionizable amino acids. We have cysteine, and we have lysine. Now, for the case of cysteine, the side chain group that is ionizable is the following group. So notice the sulfur atom contains an h atom. | Isoelectric Focusing and Isoelectric Point .txt |
We have cysteine, and we have lysine. Now, for the case of cysteine, the side chain group that is ionizable is the following group. So notice the sulfur atom contains an h atom. But when the PH value reaches the PKA value of the side chain group, namely 8.3, what that means is this will begin to lose our h atom. And at the PH value of 8.3, exactly half of the cysteine amino acids will exist in this form, and the other half will exist in this form with a negative charge on that sulfur. Now, if we go above 8.3, then this group will predominate. | Isoelectric Focusing and Isoelectric Point .txt |
But when the PH value reaches the PKA value of the side chain group, namely 8.3, what that means is this will begin to lose our h atom. And at the PH value of 8.3, exactly half of the cysteine amino acids will exist in this form, and the other half will exist in this form with a negative charge on that sulfur. Now, if we go above 8.3, then this group will predominate. If we go below 8.3, this group will predominate. Now, for the case of Lysine, the end of the side chain group that is ionizable is this group shown here. So the same exact thing is true for this particular group. | Isoelectric Focusing and Isoelectric Point .txt |
If we go below 8.3, this group will predominate. Now, for the case of Lysine, the end of the side chain group that is ionizable is this group shown here. So the same exact thing is true for this particular group. At this PH value. When the PH is equal to the PKA of this group of 10.8, then half of them will exist in this form. The other half will exist in this form. | Isoelectric Focusing and Isoelectric Point .txt |
At this PH value. When the PH is equal to the PKA of this group of 10.8, then half of them will exist in this form. The other half will exist in this form. If we go below a PH of 10.8, this group will predominate. If we go above a PH of 10.8, this is the group that will predominate. And the same thing is true for the other five readily ionizable amino acids. | Isoelectric Focusing and Isoelectric Point .txt |
If we go below a PH of 10.8, this group will predominate. If we go above a PH of 10.8, this is the group that will predominate. And the same thing is true for the other five readily ionizable amino acids. Now, since proteins consist of different combinations of these readily ionizable amino acids, what that means is they will have different net charge values at some specific PH value. For example, they will have different net charges at the physiological PH of around seven. Now, what it also means is that every protein will have a unique PH value at which the overall net charge on that protein, on that polypeptide, will be zero. | Isoelectric Focusing and Isoelectric Point .txt |
Now, since proteins consist of different combinations of these readily ionizable amino acids, what that means is they will have different net charge values at some specific PH value. For example, they will have different net charges at the physiological PH of around seven. Now, what it also means is that every protein will have a unique PH value at which the overall net charge on that protein, on that polypeptide, will be zero. And this will be the case. At a specific PH value, all the charges on all our amino acids on that protein will exactly cancel one another out. The net charge will be zero. | Isoelectric Focusing and Isoelectric Point .txt |
And this will be the case. At a specific PH value, all the charges on all our amino acids on that protein will exactly cancel one another out. The net charge will be zero. And this specific point is a property of that protein because the protein is unique. It consists of a specific combination of these amino acids. In fact, the PH value at which the protein has a net charge of zero is given a special name. | Isoelectric Focusing and Isoelectric Point .txt |
And this specific point is a property of that protein because the protein is unique. It consists of a specific combination of these amino acids. In fact, the PH value at which the protein has a net charge of zero is given a special name. It's called the isoelectric point, or simply pi. So every protein contains this isoelectric point. Now, some proteins, if they consist of the same exact combination of ionizable amino acids, they will have the same isoelectric point. | Isoelectric Focusing and Isoelectric Point .txt |
It's called the isoelectric point, or simply pi. So every protein contains this isoelectric point. Now, some proteins, if they consist of the same exact combination of ionizable amino acids, they will have the same isoelectric point. But usually proteins have different values, isoelectric point values, because they have different combinations of these ionizable amino acids. And because this is another property of proteins that is unique to most proteins, we can use this property to basically purify our protein. So if we have a mixture of different types of proteins, we can separate and isolate specific proteins from that mixture by using a method known as the isoelectric focusing method. | Isoelectric Focusing and Isoelectric Point .txt |
But usually proteins have different values, isoelectric point values, because they have different combinations of these ionizable amino acids. And because this is another property of proteins that is unique to most proteins, we can use this property to basically purify our protein. So if we have a mixture of different types of proteins, we can separate and isolate specific proteins from that mixture by using a method known as the isoelectric focusing method. So the isoelectric focusing technique is basically a method that we can use to purify and mixture proteins by using a specific property of the protein we call the isoelectric points. So let's take a look at the following diagram, which basically describes the setup of isoelectric focusing. So in the setup, we basically create a special type of gel, and we create a PH gradient along that gel. | Isoelectric Focusing and Isoelectric Point .txt |
So the isoelectric focusing technique is basically a method that we can use to purify and mixture proteins by using a specific property of the protein we call the isoelectric points. So let's take a look at the following diagram, which basically describes the setup of isoelectric focusing. So in the setup, we basically create a special type of gel, and we create a PH gradient along that gel. So let's suppose we take a gel. We take the gel, we place the gel into a special apparatus, and we create a PH gradient. What that means is on one side, let's say on the left side of our gel, we're going to have a low PH acidic environment. | Isoelectric Focusing and Isoelectric Point .txt |
So let's suppose we take a gel. We take the gel, we place the gel into a special apparatus, and we create a PH gradient. What that means is on one side, let's say on the left side of our gel, we're going to have a low PH acidic environment. On the other end, on the right side, we're going to have a high PH, a basic environment. Now, we're also going to connect both ends of that gel to a voltage source. We're going to create an electric potential difference between the two sides, and that will create an electric field. | Isoelectric Focusing and Isoelectric Point .txt |
On the other end, on the right side, we're going to have a high PH, a basic environment. Now, we're also going to connect both ends of that gel to a voltage source. We're going to create an electric potential difference between the two sides, and that will create an electric field. And we'll see why that's important. Just a moment. So once we set up this apparatus, what we do next is we take our mixture of proteins and we essentially place it into our gel. | Isoelectric Focusing and Isoelectric Point .txt |
And we'll see why that's important. Just a moment. So once we set up this apparatus, what we do next is we take our mixture of proteins and we essentially place it into our gel. Now, what will begin to happen? Well, what will begin to happen is the proteins will begin to migrate, they will begin to move. Why? | Isoelectric Focusing and Isoelectric Point .txt |
Now, what will begin to happen? Well, what will begin to happen is the proteins will begin to migrate, they will begin to move. Why? Well, because the proteins will have a net charge. And whenever they have a net charge, they will move within an electric field as a result of the interaction between the electric field and the charge, the net charge on that protein. So, for instance, if we take a protein that contains a net positive charge and we place it into our field, it will begin to move towards the negative end. | Isoelectric Focusing and Isoelectric Point .txt |
Well, because the proteins will have a net charge. And whenever they have a net charge, they will move within an electric field as a result of the interaction between the electric field and the charge, the net charge on that protein. So, for instance, if we take a protein that contains a net positive charge and we place it into our field, it will begin to move towards the negative end. And if we take a protein that contains a net negative charge, it will begin to move away from this end and towards this positively charged end. Now, the proteins will continue moving along our gel until they reach the PH value at which the overall charge is zero. And when the overall charge is zero, because there is no net charge, those proteins will no longer move along that electric field. | Isoelectric Focusing and Isoelectric Point .txt |
And if we take a protein that contains a net negative charge, it will begin to move away from this end and towards this positively charged end. Now, the proteins will continue moving along our gel until they reach the PH value at which the overall charge is zero. And when the overall charge is zero, because there is no net charge, those proteins will no longer move along that electric field. So when the protein reaches its specific isoelectric point, the pi value, it will be, it will stop moving within that gel. And so if we, for example, have a mixture of three proteins that each have their own unique ISO electric point value, and we place them into our mixture, they will separate until they will separate, and they will stop moving when they reach their pi value. So for protein one, the pi value is acidic, or relatively acidic. | Isoelectric Focusing and Isoelectric Point .txt |
So when the protein reaches its specific isoelectric point, the pi value, it will be, it will stop moving within that gel. And so if we, for example, have a mixture of three proteins that each have their own unique ISO electric point value, and we place them into our mixture, they will separate until they will separate, and they will stop moving when they reach their pi value. So for protein one, the pi value is acidic, or relatively acidic. For protein three, the pi value is relatively basic. And for protein two, it's somewhere in the middle, so it's essentially neutral. So once again, in isoelectric focusing, a gel with a PH gradient is created. | Isoelectric Focusing and Isoelectric Point .txt |
For protein three, the pi value is relatively basic. And for protein two, it's somewhere in the middle, so it's essentially neutral. So once again, in isoelectric focusing, a gel with a PH gradient is created. The two ends are connected to a voltage source, a battery, and the proteins are placed into our gel. Now, each protein will move due to the presence of an electric field as a result of that battery source. And so when they reach their pi value, the isoelectric point, they will stop moving because the net charge at the pi value of the protein is zero. | Isoelectric Focusing and Isoelectric Point .txt |
The two ends are connected to a voltage source, a battery, and the proteins are placed into our gel. Now, each protein will move due to the presence of an electric field as a result of that battery source. And so when they reach their pi value, the isoelectric point, they will stop moving because the net charge at the pi value of the protein is zero. Now, of course, this method is not very useful if these three proteins have the same combination, have the same number of these ionizable amino acids, because what that means is these three proteins will have the same exact value for the isoelectric point. So they have to have a different isoelric point value for this technique to actually be useful in separating our proteins. Now, the question is, how exactly do you determine what your pi value is for a specific polypeptide? | Isoelectric Focusing and Isoelectric Point .txt |
Now, of course, this method is not very useful if these three proteins have the same combination, have the same number of these ionizable amino acids, because what that means is these three proteins will have the same exact value for the isoelectric point. So they have to have a different isoelric point value for this technique to actually be useful in separating our proteins. Now, the question is, how exactly do you determine what your pi value is for a specific polypeptide? Now, before we determine what the pi value of specific proteins is, let's ask the following question. How do you determine what the pi value is of a single amino acid? So let's take a look at the following four cases. | Isoelectric Focusing and Isoelectric Point .txt |
Now, before we determine what the pi value of specific proteins is, let's ask the following question. How do you determine what the pi value is of a single amino acid? So let's take a look at the following four cases. There are four cases that we basically have to remember. So case number one, let's suppose that the amino acid is not ionizable. If that's the case, if the side chain is not ionizable, then to find the pi value of that particular amino acid, to find the isoelectric point, we simply sum up and we take the average of the PKA values of the terminal alpha amino group and the terminal carboxyl amino group and the terminal carboxyl group of that particular amino acid. | Isoelectric Focusing and Isoelectric Point .txt |
There are four cases that we basically have to remember. So case number one, let's suppose that the amino acid is not ionizable. If that's the case, if the side chain is not ionizable, then to find the pi value of that particular amino acid, to find the isoelectric point, we simply sum up and we take the average of the PKA values of the terminal alpha amino group and the terminal carboxyl amino group and the terminal carboxyl group of that particular amino acid. Remember, every single amino acid contains an a terminal alpha carboxyl group and a terminal alpha amino group. And those two groups are also capable of losing and gaining h atoms at specific PH values. So if the side chain is non ionizable, then the isoelectric point of that amino acid is the average of the PKA values of the terminal alpha amino group and the terminal alpha carboxyl group. | Isoelectric Focusing and Isoelectric Point .txt |
Remember, every single amino acid contains an a terminal alpha carboxyl group and a terminal alpha amino group. And those two groups are also capable of losing and gaining h atoms at specific PH values. So if the side chain is non ionizable, then the isoelectric point of that amino acid is the average of the PKA values of the terminal alpha amino group and the terminal alpha carboxyl group. So one example of a nonionisable amino acid is glycine. Another example is valine. We have Alanine leucine, isolucine and so forth. | Isoelectric Focusing and Isoelectric Point .txt |
So one example of a nonionisable amino acid is glycine. Another example is valine. We have Alanine leucine, isolucine and so forth. So let's take a look at glycine. So glycine contains the h atom sidechain group, and that means it is not ionizable. Now, at some specific temperature value, the PKA of this particular alpha amino group is 8.0. | Isoelectric Focusing and Isoelectric Point .txt |
So let's take a look at glycine. So glycine contains the h atom sidechain group, and that means it is not ionizable. Now, at some specific temperature value, the PKA of this particular alpha amino group is 8.0. And for this particular alpha carboxyl group, let's say it's 3.1 at that same temperature condition. So in this particular case, all we have to do to find the pi value of this amino acid is simply take the sum of these, divide by two and we get the average. So we have eight plus 3.1, which is 11.1. | Isoelectric Focusing and Isoelectric Point .txt |
And for this particular alpha carboxyl group, let's say it's 3.1 at that same temperature condition. So in this particular case, all we have to do to find the pi value of this amino acid is simply take the sum of these, divide by two and we get the average. So we have eight plus 3.1, which is 11.1. We divide that by two, we get 5.55. So the pi value for glycine is 5.55, assuming these are our PKA values. Now these PKA values might change if we change the conditions under which this amino acid is in. | Isoelectric Focusing and Isoelectric Point .txt |
We divide that by two, we get 5.55. So the pi value for glycine is 5.55, assuming these are our PKA values. Now these PKA values might change if we change the conditions under which this amino acid is in. So in your textbook, or maybe your teacher might give you different PKA values. And that's because the temperature conditions or other conditions under which that amino acid exists in are different. So let's move on to the second case. | Isoelectric Focusing and Isoelectric Point .txt |
So in your textbook, or maybe your teacher might give you different PKA values. And that's because the temperature conditions or other conditions under which that amino acid exists in are different. So let's move on to the second case. If the side chain is ionizable and that ionizable side chain is acidic, then to find a pi value of that amino acid, we simply take the average of the PKA values of the terminal alpha carboxyl group and that side chain. So to see what we mean, let's take an example. Let's look at an ionized blamino acid that is acidic. | Isoelectric Focusing and Isoelectric Point .txt |
If the side chain is ionizable and that ionizable side chain is acidic, then to find a pi value of that amino acid, we simply take the average of the PKA values of the terminal alpha carboxyl group and that side chain. So to see what we mean, let's take an example. Let's look at an ionized blamino acid that is acidic. So we have two cases. We have aspartate and we have glutamate. So let's take a look at aspartate. | Isoelectric Focusing and Isoelectric Point .txt |
So we have two cases. We have aspartate and we have glutamate. So let's take a look at aspartate. For aspartate, this is our side chain group, and the PKA value of Aspartate is 4.1. Now, this PKA value is the same as above. It's 3.1. | Isoelectric Focusing and Isoelectric Point .txt |
For aspartate, this is our side chain group, and the PKA value of Aspartate is 4.1. Now, this PKA value is the same as above. It's 3.1. So notice they both have negative charges. And that makes sense, because if both of these groups give the same type of charge, then to basically cancel out the positive charge, we have to average these two negative charges. And so we average these two PK values. | Isoelectric Focusing and Isoelectric Point .txt |
So notice they both have negative charges. And that makes sense, because if both of these groups give the same type of charge, then to basically cancel out the positive charge, we have to average these two negative charges. And so we average these two PK values. So 4.1 plus 3.1, that gives us 7.2. We divide that by two, that gives us 3.6. So what that means is at a PH of 3.6, these two negative charges from these two groups will exactly cancel out this positive charge found on this terminal alpha amino group. | Isoelectric Focusing and Isoelectric Point .txt |
So 4.1 plus 3.1, that gives us 7.2. We divide that by two, that gives us 3.6. So what that means is at a PH of 3.6, these two negative charges from these two groups will exactly cancel out this positive charge found on this terminal alpha amino group. And so at this particular PH value, this will have a net charge of zero. Now let's move on to case number three. Let's suppose we have an ionizable amino acid, but it is basic. | Isoelectric Focusing and Isoelectric Point .txt |
And so at this particular PH value, this will have a net charge of zero. Now let's move on to case number three. Let's suppose we have an ionizable amino acid, but it is basic. So that means there are three different amino acids that fit this category. So we have Lysine, we have arginine and we have HistoGene. Now in this particular case, what we have to do is we basically take the sum of the PKA value of that side chain group and the PKA value of the alpha amino group. | Isoelectric Focusing and Isoelectric Point .txt |
So that means there are three different amino acids that fit this category. So we have Lysine, we have arginine and we have HistoGene. Now in this particular case, what we have to do is we basically take the sum of the PKA value of that side chain group and the PKA value of the alpha amino group. We divide that by two, we get the average, and that is our isoelectric point. So let's take a look at lysine. So Lysine contains this side chain group, and the PK value of Lysine is around 10.8. | Isoelectric Focusing and Isoelectric Point .txt |
We divide that by two, we get the average, and that is our isoelectric point. So let's take a look at lysine. So Lysine contains this side chain group, and the PK value of Lysine is around 10.8. Now, the PK value of this alpha terminal group, alpha amino terminal group is eight. So notice once again, in this case we have two negative charges on two different groups. In this case, we have two positive charges on two different groups. | Isoelectric Focusing and Isoelectric Point .txt |
Now, the PK value of this alpha terminal group, alpha amino terminal group is eight. So notice once again, in this case we have two negative charges on two different groups. In this case, we have two positive charges on two different groups. So now, instead of summing this and dividing by two, we summon this, divide that by two. So we get 10.8 plus eight. That's 18.8. | Isoelectric Focusing and Isoelectric Point .txt |
So now, instead of summing this and dividing by two, we summon this, divide that by two. So we get 10.8 plus eight. That's 18.8. Divided by two gives us 9.4. So the pi, the isoelectric point for this amino acid, which is basically Lysine, is equal to 9.8. So at a PH of 9.8, these two charges will exactly cancel out this negative charge that is found on the alpha carboxyl group. | Isoelectric Focusing and Isoelectric Point .txt |
Divided by two gives us 9.4. So the pi, the isoelectric point for this amino acid, which is basically Lysine, is equal to 9.8. So at a PH of 9.8, these two charges will exactly cancel out this negative charge that is found on the alpha carboxyl group. And finally, let's move on to case four. So, if we have an ionizable side chain group, but it is neither basic nor acidic, so we're basically dealing with two cases. And these two cases are 15 and tyrosine. | Isoelectric Focusing and Isoelectric Point .txt |
And finally, let's move on to case four. So, if we have an ionizable side chain group, but it is neither basic nor acidic, so we're basically dealing with two cases. And these two cases are 15 and tyrosine. If the amino acids are 15 or tyrosine, to calculate our pi value, we have to determine what the middle PKA value is out of the three different PKA values. And then we take that middle value and we basically sum it with the terminal alpha carboxyl PK value and we divide that by two. So to see what we mean, let's take a look at the following example. | Isoelectric Focusing and Isoelectric Point .txt |
If the amino acids are 15 or tyrosine, to calculate our pi value, we have to determine what the middle PKA value is out of the three different PKA values. And then we take that middle value and we basically sum it with the terminal alpha carboxyl PK value and we divide that by two. So to see what we mean, let's take a look at the following example. So, this is our tyrosine amino acid. So, tyrosine has an ionizable side chain group, but it is neither basic nor acidic. So the side chain group is this female group. | Isoelectric Focusing and Isoelectric Point .txt |
So, this is our tyrosine amino acid. So, tyrosine has an ionizable side chain group, but it is neither basic nor acidic. So the side chain group is this female group. So the PK value of this is 10.9. So in this particular case, because it is ionizable but neither basic nor acidic, what that means is out of these three PKA values, we have to find a middle PKA value. So we have 10.93.1 and eight. | Isoelectric Focusing and Isoelectric Point .txt |
So the PK value of this is 10.9. So in this particular case, because it is ionizable but neither basic nor acidic, what that means is out of these three PKA values, we have to find a middle PKA value. So we have 10.93.1 and eight. So Diaz is our middle PK value. And then we average this value and the PK value for the alpha carboxyl terminal group. So we take 3.1, we added to eight, we get 11.1. | Isoelectric Focusing and Isoelectric Point .txt |
So we said that in skeleton muscle cells we have the enzyme known as glycogen phosphorylase that can be regulated. And that in turn regulates the breakdown of glycogen. Now, in liver cells, things are slightly different, and that's because liver cells have a different function than of skeletal muscle cells. So in liver cells that's our goal is to actually regulate the concentration of glucose inside our blood. So our liver is responsible for regulating the concentration of glucose in the blood. And what that means is liver cells can actually mobilize glycogen by breaking down to glucose, but they don't actually use that glucose to form ATP. | Regulating Glycogen Breakdown in Liver .txt |
So in liver cells that's our goal is to actually regulate the concentration of glucose inside our blood. So our liver is responsible for regulating the concentration of glucose in the blood. And what that means is liver cells can actually mobilize glycogen by breaking down to glucose, but they don't actually use that glucose to form ATP. Instead, they can release that glucose into the blood to basically increase the concentration of glucose in the blood when the blood glucose levels drop below normal. Now, how exactly is glycogen breakdown controlled in the liver? So in the liver, we also regulate the breakdown of glycogen by regulating the allosteric enzyme we call glycogen phosphorylase. | Regulating Glycogen Breakdown in Liver .txt |
Instead, they can release that glucose into the blood to basically increase the concentration of glucose in the blood when the blood glucose levels drop below normal. Now, how exactly is glycogen breakdown controlled in the liver? So in the liver, we also regulate the breakdown of glycogen by regulating the allosteric enzyme we call glycogen phosphorylase. But the glycogen phosphorase inside liver cells is slightly different than the phosphorase that we find inside skeletal muscle cells. So essentially, the liver phosphorase is an isozyme version of the muscle phosphorase. They're pretty much the same molecule with some minor differences. | Regulating Glycogen Breakdown in Liver .txt |
But the glycogen phosphorase inside liver cells is slightly different than the phosphorase that we find inside skeletal muscle cells. So essentially, the liver phosphorase is an isozyme version of the muscle phosphorase. They're pretty much the same molecule with some minor differences. And one important minor difference between liver phosphorylase and muscle phosphorase is that liver phosphorylase is actually sensitive to glucose molecules. Glucose is an allosteric effector. More specifically, it's an allosteric inhibitor of phosphorase. | Regulating Glycogen Breakdown in Liver .txt |
And one important minor difference between liver phosphorylase and muscle phosphorase is that liver phosphorylase is actually sensitive to glucose molecules. Glucose is an allosteric effector. More specifically, it's an allosteric inhibitor of phosphorase. So let's take a look at the following diagram. So, this diagram describes the fully active r state of phosphorace A found in the liver, and the T state, inactive state. Office Fourlase A of the liver. | Regulating Glycogen Breakdown in Liver .txt |
So let's take a look at the following diagram. So, this diagram describes the fully active r state of phosphorace A found in the liver, and the T state, inactive state. Office Fourlase A of the liver. So essentially, when glucose molecules bind into a specific allosteric regulating side shown here and here, what we have is a transition from the R state, the fully active state, where the activity of the enzyme is high, to the inactive state, the T state, where the activity of the enzyme is low. Now, we can have two different situations. We can basically have a situation in which the blood glucose levels are low, or we can have a situation where the glucose blood level is high. | Regulating Glycogen Breakdown in Liver .txt |
So essentially, when glucose molecules bind into a specific allosteric regulating side shown here and here, what we have is a transition from the R state, the fully active state, where the activity of the enzyme is high, to the inactive state, the T state, where the activity of the enzyme is low. Now, we can have two different situations. We can basically have a situation in which the blood glucose levels are low, or we can have a situation where the glucose blood level is high. So let's suppose we have a high blood glucose level, and this happens after we ingest some type of carbohydrate rich meal. So when blood glucose levels are high, what happens is glucose will act as an allosteric inhibitor. It will bind onto special regulatory sites, allosteric sites. | Regulating Glycogen Breakdown in Liver .txt |
So let's suppose we have a high blood glucose level, and this happens after we ingest some type of carbohydrate rich meal. So when blood glucose levels are high, what happens is glucose will act as an allosteric inhibitor. It will bind onto special regulatory sites, allosteric sites. And once they bind, they will create a conformational change in the structure of this phosphoralase A of the liver. And it will basically shift the equilibrium toward the T state. In the T state, the enzyme is not active, it has low activity, and so it will not break down glycogen into glucose. | Regulating Glycogen Breakdown in Liver .txt |
And once they bind, they will create a conformational change in the structure of this phosphoralase A of the liver. And it will basically shift the equilibrium toward the T state. In the T state, the enzyme is not active, it has low activity, and so it will not break down glycogen into glucose. And that makes sense because after we ingest the meal rich in sugar molecules. We don't want to produce and release any more glucose molecules into the blood. Now, what about when we have low blood glucose levels? | Regulating Glycogen Breakdown in Liver .txt |
And that makes sense because after we ingest the meal rich in sugar molecules. We don't want to produce and release any more glucose molecules into the blood. Now, what about when we have low blood glucose levels? Well, when we have low blood glucose levels, we're essentially going from this T state to this r state. So when we have very low concentration of glucose in the blood, these glucose molecules will essentially remove themselves. And once they remove themselves, a conformational change takes place that shifts the equilibrium toward the r state. | Regulating Glycogen Breakdown in Liver .txt |
Well, when we have low blood glucose levels, we're essentially going from this T state to this r state. So when we have very low concentration of glucose in the blood, these glucose molecules will essentially remove themselves. And once they remove themselves, a conformational change takes place that shifts the equilibrium toward the r state. And in the rstate the enzyme is fully active and it will bite to glycogen and begin breaking down glycogen into glucose and then the glucose will be removed into the blood plasma. Now remember, in skeleton muscle cells we have phosphorase A and phosphorace B. In liver cells we also have phosphorase A and phosphorase B. | Regulating Glycogen Breakdown in Liver .txt |
And in the rstate the enzyme is fully active and it will bite to glycogen and begin breaking down glycogen into glucose and then the glucose will be removed into the blood plasma. Now remember, in skeleton muscle cells we have phosphorase A and phosphorace B. In liver cells we also have phosphorase A and phosphorase B. But unlike phosphorase A, the liver phosphorase B is not actually sensitive to glucose molecules. In addition, when we discuss skeleton muscle cells, we saw that in skeleton muscle cells, amp adenosine monophosphate is an allosteric activator of phosphorase B. But in liver cells, the phosphorase B of liver cells does not respond to amp molecules. | Regulating Glycogen Breakdown in Liver .txt |
But unlike phosphorase A, the liver phosphorase B is not actually sensitive to glucose molecules. In addition, when we discuss skeleton muscle cells, we saw that in skeleton muscle cells, amp adenosine monophosphate is an allosteric activator of phosphorase B. But in liver cells, the phosphorase B of liver cells does not respond to amp molecules. And this is primarily because unlike in skeleton muscle cells, liver cells do not actually experience a change in the energy charge of the cell. So we see that the energy charge inside liver cells remains relatively constant. And what that means is amp molecules do not actually affect phosphorase B. | Regulating Glycogen Breakdown in Liver .txt |
And this is primarily because unlike in skeleton muscle cells, liver cells do not actually experience a change in the energy charge of the cell. So we see that the energy charge inside liver cells remains relatively constant. And what that means is amp molecules do not actually affect phosphorase B. So to summarize, let's take a look at the following two diagrams. So if we have low blood glucose levels, what will begin to happen is these glucose will essentially depart from these regulatory sites and that will shift the equilibrium toward the r state. It will activate phosphorase A of the liver and that will initiate glycogen breakdown. | Regulating Glycogen Breakdown in Liver .txt |
In the previous lecture, we focused on step one of the citric acid cycle, and we saw that in step one, we basically take an acetyl group and attach it onto an oxalo acetate molecule to form a six carbon intermediate known as the citrate molecule. And so in this lecture, I'd like to focus on what happens next. So we're going to focus on steps two, three, and four of the citric acid cycle. And so so let's begin with step number two. Now, the entire point of step number two is basically to take the citrate molecule and to prepare it for oxidative decarboxylation that will take place in step three and step four of the citric acid cycle. So in these two steps, we're basically going to produce carbon dioxide molecules, and we're going to abstract those high energy electrons that we're going to use on the electron transport chain. | Step 2-4 of Citric Acid Cycle .txt |
And so so let's begin with step number two. Now, the entire point of step number two is basically to take the citrate molecule and to prepare it for oxidative decarboxylation that will take place in step three and step four of the citric acid cycle. So in these two steps, we're basically going to produce carbon dioxide molecules, and we're going to abstract those high energy electrons that we're going to use on the electron transport chain. But before steps three and four take place, we have to prepare the citrate molecule. And the way that we prepare that citrate molecule is by actually changing the position of this hydroxyl group. So citrate and isocytrate are actually isomers. | Step 2-4 of Citric Acid Cycle .txt |
But before steps three and four take place, we have to prepare the citrate molecule. And the way that we prepare that citrate molecule is by actually changing the position of this hydroxyl group. So citrate and isocytrate are actually isomers. They have the same exact molecular formula, but they differ in the position of this hydroxyl group. On the citrate, the hydroxyl is attached onto this carbon. Let's call it carbon three. | Step 2-4 of Citric Acid Cycle .txt |
They have the same exact molecular formula, but they differ in the position of this hydroxyl group. On the citrate, the hydroxyl is attached onto this carbon. Let's call it carbon three. And on this molecule, the hydroxyl is instead attached onto this carbon here. And we see that to go from this reaction to this product, we have to go through an intermediate. And so this step two is actually a two step process. | Step 2-4 of Citric Acid Cycle .txt |
And on this molecule, the hydroxyl is instead attached onto this carbon here. And we see that to go from this reaction to this product, we have to go through an intermediate. And so this step two is actually a two step process. So in process one of step two, we have a dehydration reaction. Why? Well, because we want to basically remove this hydroxyl group. | Step 2-4 of Citric Acid Cycle .txt |
So in process one of step two, we have a dehydration reaction. Why? Well, because we want to basically remove this hydroxyl group. And in addition, we remove this H to form the water molecule and form the double bond between this carbon and this carbon here. And once we form this double bond, this water molecule that comes in in step two will basically undergo a hydration reaction. The water will act as a nucleophile, and instead of attacking this carbon, it will attack this carbon. | Step 2-4 of Citric Acid Cycle .txt |
And in addition, we remove this H to form the water molecule and form the double bond between this carbon and this carbon here. And once we form this double bond, this water molecule that comes in in step two will basically undergo a hydration reaction. The water will act as a nucleophile, and instead of attacking this carbon, it will attack this carbon. Because if the water molecule attacked this carbon, we would have simply reformed the citrate molecule. But if the water attacks this carbon, which is basically less hindered because it contains a smaller group on this side compared to this large group here, the water molecule is able to actually attack from this side because of less hindrance. And so once it attacks that side, we form the isocitrate molecule. | Step 2-4 of Citric Acid Cycle .txt |
Because if the water molecule attacked this carbon, we would have simply reformed the citrate molecule. But if the water attacks this carbon, which is basically less hindered because it contains a smaller group on this side compared to this large group here, the water molecule is able to actually attack from this side because of less hindrance. And so once it attacks that side, we form the isocitrate molecule. So the entire point of this step is to basically prepare the citrate molecule for oxidative decorboxylation that takes place in step three as well as step four. Now, this double bonded intermediate molecule is known as cisaconitate. And because of this cysticonitate, the enzyme that catalyzes step two is known as aconitase. | Step 2-4 of Citric Acid Cycle .txt |
So the entire point of this step is to basically prepare the citrate molecule for oxidative decorboxylation that takes place in step three as well as step four. Now, this double bonded intermediate molecule is known as cisaconitate. And because of this cysticonitate, the enzyme that catalyzes step two is known as aconitase. So once again, once citrate is formed in step one of the citric acid cycle, it must be transformed into its isomeric form, isocitrate. And this reaction, we basically transfer a hydroxyl group from the third carbon onto the adjacent carbon shown here. And what this process does, once again, is it prepares the molecule for a decarboxylation reaction that we'll talk about in the next step. | Step 2-4 of Citric Acid Cycle .txt |
So once again, once citrate is formed in step one of the citric acid cycle, it must be transformed into its isomeric form, isocitrate. And this reaction, we basically transfer a hydroxyl group from the third carbon onto the adjacent carbon shown here. And what this process does, once again, is it prepares the molecule for a decarboxylation reaction that we'll talk about in the next step. Now, the enzyme that catalyzes this step is known as a connotase. And this aconitase actually contains an iron sulfur component. And that's why this molecule, the connotase enzyme, is known as an iron sulfur enzyme. | Step 2-4 of Citric Acid Cycle .txt |
Now, the enzyme that catalyzes this step is known as a connotase. And this aconitase actually contains an iron sulfur component. And that's why this molecule, the connotase enzyme, is known as an iron sulfur enzyme. An iron sulfur protein now actually contains a ratio of four iron to four sulfur inorganic sulfide atoms. And this complex is found on the active side, and it binds not the hydroxyl onto the carboxylate ion group of the citrate. And that holds the citrate molecules within the active side and allows the catalysis to actually take place. | Step 2-4 of Citric Acid Cycle .txt |
An iron sulfur protein now actually contains a ratio of four iron to four sulfur inorganic sulfide atoms. And this complex is found on the active side, and it binds not the hydroxyl onto the carboxylate ion group of the citrate. And that holds the citrate molecules within the active side and allows the catalysis to actually take place. So, once again, step two is a two step process. So we have this dehydration and hydration that is catalyzed by the connotase, which is an iron sulfur protein because it uses the iron sulfur complex to carry out these two reactions. Now, once we form the isocitrate molecule, now this six carbon molecule is ready to undergo the first oxidative decorboxylation step of the citric acid cycle. | Step 2-4 of Citric Acid Cycle .txt |
So, once again, step two is a two step process. So we have this dehydration and hydration that is catalyzed by the connotase, which is an iron sulfur protein because it uses the iron sulfur complex to carry out these two reactions. Now, once we form the isocitrate molecule, now this six carbon molecule is ready to undergo the first oxidative decorboxylation step of the citric acid cycle. And this is what happens in step three. So once the isocitrate is formed, it is ready to undergo the first oxidative decorboxylation step. And this reaction is catalyzed by isocytrate dehydrogenase. | Step 2-4 of Citric Acid Cycle .txt |
And this is what happens in step three. So once the isocitrate is formed, it is ready to undergo the first oxidative decorboxylation step. And this reaction is catalyzed by isocytrate dehydrogenase. Why dehydrogenase? Well, remember, a dehydrogenase is an enzyme that basically abstracts those electrons attached onto the H ion to basically form that reduced NADH molecule. So in this particular case, in the same exact way that we have a two step process here, we also have a two step process here. | Step 2-4 of Citric Acid Cycle .txt |
Why dehydrogenase? Well, remember, a dehydrogenase is an enzyme that basically abstracts those electrons attached onto the H ion to basically form that reduced NADH molecule. So in this particular case, in the same exact way that we have a two step process here, we also have a two step process here. And in the first step of step three, we take the isocytrade and we reacted with the nicotine amide adenine dinucleotide in the oxidized form. And so in this process, the NAD plus is actually reduced into the NADH, and the isocitrate molecule is oxidized to form the oxylosuxanate. And we also release this H plus ion. | Step 2-4 of Citric Acid Cycle .txt |
And in the first step of step three, we take the isocytrade and we reacted with the nicotine amide adenine dinucleotide in the oxidized form. And so in this process, the NAD plus is actually reduced into the NADH, and the isocitrate molecule is oxidized to form the oxylosuxanate. And we also release this H plus ion. So the first reaction involves abstraction of a pair of high energy electrons to form the NADH. And this high energy intermediate known as oxalosuxnate and oxylosuxanate is unstable because it is a beto keto acid. So remember from organic chemistry that beta keto acids are generally unstable molecules. | Step 2-4 of Citric Acid Cycle .txt |
So the first reaction involves abstraction of a pair of high energy electrons to form the NADH. And this high energy intermediate known as oxalosuxnate and oxylosuxanate is unstable because it is a beto keto acid. So remember from organic chemistry that beta keto acids are generally unstable molecules. Now, the NADH that we produced will be used by the electron transport chain, as we'll discuss in a future lecture. So now let's move on to step two of this process that takes place in step three. So in the next step, we take that oxylosuxtonate and bivactivity of the same enzyme, isocitrate dehydrogenase. | Step 2-4 of Citric Acid Cycle .txt |
Now, the NADH that we produced will be used by the electron transport chain, as we'll discuss in a future lecture. So now let's move on to step two of this process that takes place in step three. So in the next step, we take that oxylosuxtonate and bivactivity of the same enzyme, isocitrate dehydrogenase. We mix it with an H plus ion, and we basically form a molecule known as alpha ketonoglutrate. So the highly unstable oxylosuxanate can now undergo a decarboxylation reaction. So this was the oxidation reduction reaction, and this is the decarboxylation step. | Step 2-4 of Citric Acid Cycle .txt |
We mix it with an H plus ion, and we basically form a molecule known as alpha ketonoglutrate. So the highly unstable oxylosuxanate can now undergo a decarboxylation reaction. So this was the oxidation reduction reaction, and this is the decarboxylation step. And actually, as we'll discuss in much more detail in a future lecture, this essentially is the step, the formation of the alpha ketoglutter rate is the step that actually determines the rate at which the citric acid cycle actually takes place. So this is a very important step. And if we sum up these two steps, these two reactions of step three, this is the net reaction that we're going to get. | Step 2-4 of Citric Acid Cycle .txt |
And actually, as we'll discuss in much more detail in a future lecture, this essentially is the step, the formation of the alpha ketoglutter rate is the step that actually determines the rate at which the citric acid cycle actually takes place. So this is a very important step. And if we sum up these two steps, these two reactions of step three, this is the net reaction that we're going to get. Notice that the oxylosuxanate molecules don't appear any of the sides because they cancel out. So if we sum up this reaction with this reaction, this cancels out, and so does this, as well as the H plus here and H plus here. So this is the net reaction that we get on the reactant side, the isocytrate that we produce in step two and the NAD plus that acts as the carrier and picks up those two electrons that we abstract from the isocytrate, we form the NADH. | Step 2-4 of Citric Acid Cycle .txt |
Notice that the oxylosuxanate molecules don't appear any of the sides because they cancel out. So if we sum up this reaction with this reaction, this cancels out, and so does this, as well as the H plus here and H plus here. So this is the net reaction that we get on the reactant side, the isocytrate that we produce in step two and the NAD plus that acts as the carrier and picks up those two electrons that we abstract from the isocytrate, we form the NADH. The carbon dioxide molecule is removed from the isocytrate, and we form this alpha ketoglutrate molecule. Now let's move on to step four. In step four, once again, we have another oxidative decarboxylation step. | Step 2-4 of Citric Acid Cycle .txt |
The carbon dioxide molecule is removed from the isocytrate, and we form this alpha ketoglutrate molecule. Now let's move on to step four. In step four, once again, we have another oxidative decarboxylation step. We're going to remove yet another carbon dioxide in the process abstracting the pair of high energy electrons to basically form the reduced NADH molecule, which eventually will be used by the electron transport chain to generate those high energy adenosine triphosphate molecules. And in this step, we actually use the coenzyme A, the same coenzyme A that we use in Pyruvate decarboxylation. So the next step is a second oxidative decarboxylation reaction of the citric acid cycle. | Step 2-4 of Citric Acid Cycle .txt |
We're going to remove yet another carbon dioxide in the process abstracting the pair of high energy electrons to basically form the reduced NADH molecule, which eventually will be used by the electron transport chain to generate those high energy adenosine triphosphate molecules. And in this step, we actually use the coenzyme A, the same coenzyme A that we use in Pyruvate decarboxylation. So the next step is a second oxidative decarboxylation reaction of the citric acid cycle. This step involves the conversion of the alpha ketoglutrate into the succinil coenzy, and this is what the reaction looks like. So this is the net reaction. On the reactant side, we have the product of step three, the alpha key to glutrate in the presence of the mad plus. | Step 2-4 of Citric Acid Cycle .txt |
This step involves the conversion of the alpha ketoglutrate into the succinil coenzy, and this is what the reaction looks like. So this is the net reaction. On the reactant side, we have the product of step three, the alpha key to glutrate in the presence of the mad plus. We need this because this acts as the carrier to actually abstract those electrons. And we have the Co enzyme, the coenzyme A COA. And on the product side, we essentially attach we remove this component that produces the carbon dioxide, and we attach the coenzyme a onto this bond to form the high energy thio ester bond. | Step 2-4 of Citric Acid Cycle .txt |
We need this because this acts as the carrier to actually abstract those electrons. And we have the Co enzyme, the coenzyme A COA. And on the product side, we essentially attach we remove this component that produces the carbon dioxide, and we attach the coenzyme a onto this bond to form the high energy thio ester bond. And this is the bond that will be broken in the steps to come as we'll discuss in the next several electrodes. Now, this succinct coenzyme A basically is the product of step four. And the enzyme that catalyzes step four is known as alpha ketoglu rate because this is a substrate molecule that binds into the enzyme dehydrogenase complex. | Step 2-4 of Citric Acid Cycle .txt |
And this is the bond that will be broken in the steps to come as we'll discuss in the next several electrodes. Now, this succinct coenzyme A basically is the product of step four. And the enzyme that catalyzes step four is known as alpha ketoglu rate because this is a substrate molecule that binds into the enzyme dehydrogenase complex. And in fact, this complex is very similar to the complex that catalyze step one of the citric acid cycle. How is it similar? Well, this complex, just like that complex, also consists of three different types of enzymes, and it also uses many different types of Cofactors. | Step 2-4 of Citric Acid Cycle .txt |
And in fact, this complex is very similar to the complex that catalyze step one of the citric acid cycle. How is it similar? Well, this complex, just like that complex, also consists of three different types of enzymes, and it also uses many different types of Cofactors. So we have the E one enzyme that is known as alpha ketoglutrade dehydrogenase, that uses the TPP. So thiamine pyrophosphate cofactor we have the E two known as dihydrolypoil succinct transferase that uses the lipoic acid derivative. And we have E three, dihydroly pool dehydrogenase that uses the fad. | Step 2-4 of Citric Acid Cycle .txt |
And what that means is they create a network of pipes inside our body that allows the movement of our blood. And that's important because blood carries not only nutrients, electrolytes, minerals and vitamins, but it also carries hormones, waste products and different types of cells to different parts of our body. Now blood vessels come in three different types. We have arteries and we have veins and we also have capillary. So let's begin by focusing on our artery. Now arteries vary in size. | Types of Blood Vessels .txt |
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