Protein Synthesis (Part 1) - Grade 12 Life Sciences (2026)

So guys, when they say protein synthesis, what do you think we are talking about? According to what I sent you guys to do is homework. Homework was to study protein synthesis. And some people did study, some people showed me their work. But I just said you can just study, it is fine. But it shows that you guys did put effort to this. So I want to hear from at least four people. You don't give the full information. Just give a little bit of information. Then someone continues from there. So I'll open the panel. You guys raise hands. Tell me what you know about protein synthesis. Starting with Mugwele. Protein synthesis, I figured out it is the manufacture of proteins by the cells in the body. Okay, nice. Here's Sam. Well, sir, the process of a protein synthesis, it takes two stages, a transcription, a translation. Okay, it has got two stages, transcription and translation. Okay, very good. Who else knows something about protein synthesis? Who else found anything else that hasn't been said so far about protein synthesis? Yes, Sam. Well, sir, my colour is like DNA replication. But when it ends, it ends very differently. Hmm, cool. Wow, in the colour, what that is DNA replication? Well, sir, if you're not getting checked, the real structure of it, it clearly ends up in the DNA molecule, it unzips. Therefore, my hydrogen bonds are breakable to form two separate strands. Therefore, my free nucleoids from my nucleoplasm are sealed. Therefore, the process has got a change of order, sir. Okay, cool. Trevor? Proteins are made from amino acids. And the bond that connects amino acids is called a peptide bond. Awesome. Protein synthesis is okay in the nucleus and ribosome. Okay, cool. Yeah, so you guys have got good points. And it shows that you guys did do research properly on the protein synthesis. So now we'll be looking at it together. The reason that I tell you guys to go and do this topic alone, it is so that you guys can have a bigger idea on it from your own research. I want you guys to know how to research, okay. I'm especially impressed by how Trevor structured his work. He did send his work through. Okay, he structured it in a neat way, making it very easy to understand. So now we are just going to look first at the whole thing. What is protein synthesis? As you guys have said that basically protein synthesis is the manufacture. So it is the manufacture of proteins by the cells in a body. So basically, this is when the cells of your body are making proteins. Guys, proteins are very, very, very important in our body. They play a vital role in our body. I mean, most of the processes that happen in our body internally, they are coordinated by proteins as well as hormones and other chemicals. So for example, I gave an example last time that we've got hemoglobin. And hemoglobin is a protein that is found inside your blood. And the function of hemoglobin is to carry the oxygen in the blood when you breathe in some oxygen, okay. So proteins, they are used to maintain your hair. They maintain your nails. They help you in maintaining the organs of your body. So the cells of the body are the ones that make those proteins. So basically, we need to remember from your grade 10 that you were told that proteins are made up of amino acids. Remember guys, when I use the term monomers, even on DNA, we say that monomers are the building blocks, or these are the smaller units that are combined together to form one big thing. For example, for DNA and RNA, the nucleic acids, we say that the monomers are nucleotides because they are the ones that are smaller units that are connected together to form the nucleic acid. Similarly here, for proteins, the smaller units that needs to be combined or to be joined together, they are known as amino acids, okay. So these are the building blocks of proteins. So here in grade 12, you guys do not use any complicated diagram to represent amino acids. You just use a circular shape to represent amino acids. But if you proceed and do chemistry, maybe at the university level, you guys will learn that amino acids are way so much complicated in their chemical structure. But this block here, or this round shape, we are going to use it as a model or a diagram to represent amino acids, which are the building blocks, aka the monomers of proteins. So these are amino acids. So now furthermore, Trevor said that the amino acids, they are bonded together or they are joined together by a bond that is known as a peptide bond. So it is a peptide bond that joins two amino acids together to be able to form their required protein. So you can see that when these amino acids are joined together, they are joined by what we call the peptide bond. So please don't confuse peptide bond with weak hydrogen bond. The weak hydrogen bond, it is used to bond what and what? What is the weak hydrogen bond used to bond? Yes, Trevor? To bond two complementary nitrogenous bases. Excellent answer. If you answer questions in this way, Trevor, you are going very far. If you answer these questions in this way, you are going very far, especially in the exams. The weak hydrogen bonds, they are used to connect complementary nitrogenous bases. It's like a full answer telling you that we are bonding two complementary nitrogenous bases. So please guys, take Trevor as an example of how to answer questions. You answer in a way that expresses truly the nature of the question. So here in this case, the amino acids, they are connected by a peptide bond. So now the amino acids, what's most important that you guys should know is that amino acids, they are found in the cytoplasm of the cell. The amino acids, these monomers, these monomers, they are found where? In the cytoplasm of the cell. Guys, where is the cytoplasm of the cell? Where do we find the cytoplasm? Where do you find the cytoplasm in your cell? Closely to the colgene membrane, if I'm not mistaken. The cytoplasm, it is the fluid that is filling the entire space in the nucleus. It's a jelly-like fluid that is full in this entire space. You see this entire space, guys, I even explained to you last time, when we say that plasm, the plasm just means that it's a fluid or it's a molded substance, it's a fluid, all right? So this is a fluid that is found in the cell, that is full here in the cell, just like the nucleus, yes. Is it called the cytoplasm or the nucleoplasm? The nucleoplasm, it is the fluid found in the nucleus. That's the difference, cytoplasm found in the cell, cyto for cell, plasm for plasma, all right? It is the fluid, yes, so nucleoplasm, last time I explained to you that nucleoplasm, it is the fluid that is filling or that is found fully here inside the what? Inside the nucleus. That's why we name it as nucleo. That nucleo is for nucleus, then the plasm is for fluid in the nucleus. This yellow fluid, it is fluid in the cell. So that's cytoplasm. How would you get? Yes, all right. So basically, this space, this entire space is not really an empty space. It is the cytoplasm, which is just a jelly-like substance that is made up of at least 70% of water, all right? So this jelly-like substance, it is made up of at least 70% of water. All right, yes? Also, it is important to know the name of the amino acid. To know the names of the amino acids, they are not required to be known. They will always be given to you in the question whenever you have to use them at some point. All right, so guys, let's review this diagram of a cell that I made. Original diagram of a cell that I made here. Do you guys see the nucleus? Do you guys see the nucleus here? Yes, I do see. Yes, so the nucleus has got a nucleolus inside it. And then it has got some pores. So a nucleus has got some pores. Remember the nuclear pores? And what is the function of those pores, guys? Why do we have holes at the surface of the nucleus? At the nuclear membrane, why do we have some holes, Trevor? They act as a selective filter, allowing substances to move in and move out. Yes, so these nuclear pores or these holes that are found at the nuclear membrane, they are the ones that allow substances to get into the nucleus and substances to come out or to get out of the nucleus, okay? So it's known as nuclear pores. Then now we have got this cytoplasm, the entire space here. Then do we see the ribosomes, guys? These ribosomes, these circular structures, these are the ribosomes. Do we see them? Yes, sir. All right, cool. So I said that the amino acids, they are found... Where are they found? They are found inside the cytoplasm. So it means that at a random time or at any time, I expect to find an amino acid here. So this green shape that I'm trying to paint here is just an illustration to tell you guys that amino acids, they are found in the cytoplasm altogether. So the amino acids are found in the cytoplasm of the cell. That's where you find amino acids. Please keep this in mind. It's very important. So now we have got two organelles that are involved in protein synthesis. Guys, what is the difference between an organ and an organelle? Who knows the difference between an organ and an organelle? Yes, Trev. Sir, organelles, they are organs that are inside the cell. And then, earlier, organelles, what's the organelle, sir? Cool, awesome. But that one is correct. So our organelles, when you're talking about organelles, these are the parts of the cells, okay? But organs, they are the parts of the body, all right? So your ears and your mouth and your eyes, those are parts of your body. Those are organs. Those are your body organs. And then the organelles, those are the parts that are found inside the cell, such as the nucleus, such as the ribosomes, such as the mitochondrion, and everything else that is contained within the nucleus. So in this case, when we're talking about the two organelles, we're talking about the two parts that are involved in protein synthesis. So in protein synthesis, we have got the nucleus as well as the ribosomes. So we've got only those two organelles that are responsible for protein synthesis. Whenever they ask you, state or mention the two organelles involved in protein synthesis, you mention the nucleus as well as the ribosomes. Are we together? So here's the nucleus, here's the nucleus, and then here are the ribosomes. So furthermore, Sam told me that we have got two stages in protein synthesis. Specifically, he said that we've got transcription as well as translation. These are the two main stages of the formation of a protein or of protein synthesis. So we have got transcription. Someone said to me that transcription occurs at the nucleus. So this process of transcription, it occurs where? In the nucleus, in the nucleus, inside the nucleus. Then we have got translation. Translation happens or it occurs at the cytoplasm. Is it? In the ribosome. The ribosome. At the ribosome, not in. Yes, so transcription occurs in the nucleus, but translation occurs at the ribosomes. So I'm just going to write this point so that you guys can remember. So translation occurs at the ribosome, but transcription occurs in the nucleus. Are we clear on that? Yes. All right. So, yes, Sam? Well, Sam, I'm kind of confused. The transcription is in the outside, but at the ribosome, but outside it. Yes. So transcription, yeah, transcription occurs in the nucleus, but translation occurs at the ribosome. All right. So now let's start. OK, for us to make a protein, guys, I've already told you that the amino acids must be joined by a peptide bond to form the required protein. So basically, for us to end up having a protein, a complete protein, for us to have a complete protein, we need to have a polypeptide chain. So whenever they use the term polypeptide, just don't get surprised. When they say polypeptide, a polypeptide chain, it simply means it's a protein, guys. OK, just using scientific terms. Polypeptide chain, it means it's a what? It's a protein. Simply means that we've got a chain of amino acids that are bonded by a polypeptide bond. All right. It's a protein. How would you get that, guys, on the terms? Yeah. So you guys know the mission here. It is for us to collect amino acids from the what? From the amino, where do you find amino acid, where do you find them? Where do you find amino acid? Yes, from the cytoplasm. So our main mission for us to form proteins, it is to find amino acids in the cytoplasm and bring them to the ribosome. So just write that so that you guys know the goal, so that you guys kind of internalize this concept so that when you do complex stuff such as codons, you guys don't get lost in the complexities. So our mission here, it is to collect amino acids from the cytoplasm to the ribosome. So our whole mission for us to form a protein, we collect amino acids from the cytoplasm to the ribosome. If you just write that statement, you have actually summarized the entire process of protein synthesis. But since this is life sciences, we need to get a bit complex and look at how does that happen? How do we end up getting the amino acids to move from the cytoplasm so that they can go to the ribosome to make a protein? All right. So how does this happen? We start with the process that is known as the transcription. In full, we say it is the transcription of mRNA. So when you're saying that we are transcribing or we are doing the transcription of mRNA, it means that we are forming mRNA. So keep it in mind that during transcription of mRNA, it means we are doing what? We are forming mRNA. What is the full name of mRNA according to what we did last time? What is the full name of mRNA? It's messenger RNA. So basically, we want to form messenger RNA. And for us to form messenger RNA, we need to form it inside the nucleus. Are we together? Yes. So we need to form it inside the nucleus. All right. So let me just clear a page here. The slides are a bit messy. All right, all right, all right. So for illustration purposes, I will make sure to just create a new page dedicated to this wonderful explanation. Okay, okay. All right. So let's do the formation of mRNA. So I will illustrate the formation of mRNA or the transcription process. But you guys, for the points that you need to mention, you will take it from here. This is how you describe the process of transcription. All right. So guys, whenever you want to describe a process in life sciences, it is very crucial or it is very important for you guys to write the term transcription on top before you start explaining the process. This is otherwise known as the compulsory mark. So at some point, whenever they say describe the process shown in the diagram above, all right, you have to do it. You have to first write the name of the process. Then you put the semicolons. Then you start explaining the process. That way you will be able to get that compulsory mark. Are we together? Yes, sir. All right. So since you guys have done DNA replication, transcription is a similar, it's a similar concept. All right. But now there are terms that I need you guys to get used to. All right. So when we have got a strand of DNA, so I will draw a strand of DNA. Let me just write a strand of DNA. Remember I said that we use thick diagrams here. So please get used to them the most. So this is a strand of DNA. I will write a couple of nitrogenous bases such as A to C, G, A, C. Okay. A to C, G, A, C. Okay. Let's just save these two. It's fine. Don't need too much. All right. So do you guys that see that this is a strand of DNA? Do we all see that? Yes, I didn't draw the other strand. I just wanted to show you one strand of DNA, how it looks like. So don't be like, this is now RNA. No, this is a strand of DNA because you can see that we even have thiamine as a nitrogenous base. So when we have got three nitrogenous bases that are following each other, literally exactly what I'm saying, just take it exactly the way it is. I'm saying when you've got nitrogenous bases, three of them, like one, two, three, you just count three nitrogenous bases and they are following each other. We say that is known as a DNA base triplet. Okay. So I will label it here and make sure that you guys get used to the terms. This is known as a DNA base triplet. So a DNA base triplet is nothing complicated. It is just three nitrogenous bases that are following each other. Simply that guys, nothing too complex. Three nitrogenous bases that are found in DNA. Remember that we are talking about DNA guys here. Okay. Remember last time when we did a session about RNA, we said that three nitrogenous bases that are following each other, they are known as what? An RNA. When we did the RNA last time, who can remember? Codons. They are known as codons. Yes. Yes, you are right. Last time we said that if we have got an RNA molecule, right, a messenger RNA molecule, actually we focused on messenger RNA. If we have got a messenger RNA, a strand of messenger RNA, it will have some uracil in it, not bimine. So this cannot be, this is not mRNA. This is not mRNA. It's just a strand of DNA. But when it comes to DNA, when we have got three nitrogenous bases that are following each other is known as a DNA base triplet. So don't call it a codon. Okay. I will say not codon. So go guys to a break or come back after 10 minutes to finish off. Just go to a break. So it's known as a DNA triplet, base triplet. So when you come back from the break, we'll continue. Hey Lapo, I know that you've been enjoying this wonderful video and most likely you've been enjoying watching this handsome face in front of you, but sorry, ladies, I'm taken. I just here to tell you that educate is on the road to 100,000 subscribers by the end of 2025. So please click the subscribe button and click the notification bell so that you get notifications whenever I post new videos, I want you guys to pass. Okay. So if you make my dream true, I reach 100k subscribers. I will make your dreams come true. I will even get you to varsity. I will get you with seven distinctions. Yes. That if I've got a strand of DNA and then I see three nitrogenous bases such as adenine, thiamine and cytosine that are following each other. I call that a DNA base triplet. It's a triplet like three. Okay. Don't just call it a triplet. Just call it a DNA base triplet to say that we have got three DNA for three nitrogenous bases that are following each other in a DNA strand or in a DNA molecule. All right. So you guys know how to recognize DNA molecules, right? You now know how to recognize them, right? Yes. All right. So if we zoom into this DNA molecule that is found in the nucleus, can you see the DNA molecule here? Can you see just once? Yeah. At least one strand of the DNA molecule. Don't mind the other complexities. Just look at one strand of a DNA molecule. At least in my safe time, I just know that in my safe time mind for it to be DNA molecule. Can you see? Can you see the strands of DNA? Yes. So if we do a count, I will look at this strand particularly, this one, this one. So do you see these nitrogenous bases, which are TCT? Do you see them here? TCT. This is a DNA base triplet. If you want to call them S1, this is a what? A DNA base triplet. It's just three nitrogenous bases that are following each other. Yes, Trevor? Even if a nitrogenous base diamond repeats itself, it is still a base triplet. Yes, it is still a DNA base triplet. It doesn't matter. It doesn't matter the composition or it doesn't matter which nitrogenous base is there. As long as it's three nitrogenous bases and they are consecutive or they are following each other, then you can say it's a DNA base triplet. Are we together, Trevor? Why are they not codons? Because it's a DNA molecule. We only call them codons on an mRNA, not a DNA. Yes. So when we go to a DNA molecule, three nitrogenous bases that are following each other, they are known as a DNA base triplet. Never call them codons, guys. Please. I repeat, they are not codons. They are known as a DNA base triplet. Let's go back to this strand of DNA that I've drawn here. This one. How many DNA base triplets do we have in this one? Two, sir. We've got two DNA base triplets because we have already done this one, ATC. These three nitrogenous bases following each other, ATC, that is one DNA base triplet. And if we do the same here, we count this guanine, we count this adenine, we count this cytosine. These three nitrogenous bases following each other will make up the second DNA base triplet. So in this case, we're having two DNA base triplets. But I'm just going to write two triplets, but you guys will write two DNA base triplets. So similarly, back to this diagram, when you look inside the nucleus, a strand of DNA or a strand that has got a thymine, you know that that one is of DNA, right? As long as you have three nitrogenous bases that are following each other, that's a DNA base triplet. So how many DNA base triplets are we having on this strand, this one? On this one, how many are we having? Four. Four, right? Can we all see the four? Yes, you just count three nitrogenous bases, you're going to form one. So this is GGG, GGG. This is another three nitrogenous bases, okay? If you guys will watch it as a video, make sure that you zoom in this portion so that you see it properly. This is ACA. This is another DNA base triplet. And then this is a TCA. This is the last DNA base triplet. So if you can just zoom in a bit so that you guys can see clearly. On this strand of DNA, it's a strand of DNA, right? We have got TCT, that's one base triplet. GGG, that's another base triplet. ACA, that's another DNA base triplet. TCA, that's another DNA base triplet. Okay, are we together? In case they tell you to define DNA base triplet, you would just say that a DNA base triplet is three nitrogenous bases that are following each other, if you want to use simple English. But if you want to use a simpler term, you would say a DNA base triplet is three consecutive nitrogenous bases found on a DNA strand. Okay, I'm not going to write it down, I'll repeat. A DNA base triplet, it is three consecutive, three consecutive nitrogenous bases that are found on a strand of DNA molecule. So I repeat, a DNA base triplet is three nitrogenous bases that are consecutive, or you can say three consecutive nitrogenous bases, or three nitrogenous bases that follow each other, that are found on a DNA strand. Guys, do not, do not miss the DNA part because this is only on a DNA. If it's another molecule, if it's not a DNA strand, don't tell me about a base triplet, all right? Are we together? Yes, sir. Awesome. So now we'll do a demonstration of how we transcribe mRNA. So basically, remember that the natural shape of DNA is the double helix. So I'm going to draw a double helix structure to show that I'm having a DNA molecule. And then this DNA molecule, remember that the double helix has got a couple of nitrogenous bases in between. You guys now know how to draw the double helix structure, right? Yes, sir. All right, awesome. So the first and foremost point under transcription, after writing the term transcription, you now describe it. The first thing that happens, the DNA double helix unwinds. Guys, remember I explained the process of unwinding when we introduced DNA, to say that when you say that the double helix is unwinding, it simply means that it is untying itself, okay? Don't use the term unzip, okay? You use the term unzip here at point number two. Don't use it at point number one. All right, the DNA double helix unwinds. Don't use any other term besides unwinds. Don't use the term unties, okay? Just use the term unwinds because I explained to you guys what does unwinding mean. The unzip part, we are going to do it on point number two. Are we together? Yes, sir. So the DNA double helix unwinds, meaning that it will unwind into just a normal DNA shape. So this is a normal DNA and this DNA still has got nitrogenous bases and it's got a weak hydrogen bonds between complementary, oh, I'm now writing A and B, between complementary nitrogenous bases. Remember, we have got weak hydrogen bonds. Let's just say this is G and then let's just say this is C and then this is a C, this is G. Let me just extend my structure because I will need it to be extended, all right? And let's just say T, C, A, and then now this will be A, this will be A, G, and then this will be T. Can we all guys see what's happening here? Yeah, I don't know if it is unclear here. I'm trying my best. I don't know my pieces acting up a bit. I don't know why, but some technical glitches. Fine, G. So it is unwinded. So the first process was the DNA double helix structure. It is unwinded. That's the first thing. Then after the DNA double helix structure unwinds, what will happen? The weak hydrogen bonds between nitrogenous bases will break. This is the same as DNA replication process. That's why Sam said that the transcription process in the beginning seems like the DNA replication process, all right? So we have weak hydrogen bonds that break. So the weak hydrogen bonds between the nitrogenous bases break. Or you can say that the DNA double strand unzips. So you can say the DNA double strand unzips. This is the same thing. The DNA double strand unzips. Don't say unwind. Unzips is now different from unwind. In what way? So when these weak hydrogen bonds break, okay, when they break, it means that the strands will separate from one another. Do you kind of agree to that? Yes. Yes, so the strands will separate. So the DNA strands will separate from one another, meaning that we will have one strand. I'm just going to use this strand exactly as it is, right? I'm just going to write a copy of it here and say this is A. And then this is G. And then this is C. And then this is T. This is C. This is A. All right. So just for space, so that we can have enough space. How? This thing is not erasing. What's wrong with A? How? This thing is not erasing and then it comes and erases everything else. I don't know what's wrong with this. I really don't know. Just give me a bit of time, guys. I think my PC is acting up a bit here. Let me just exit a bit. I wonder what's his problem. My voice sounds tired, is it? Don't worry about me, guys. I'm used to this life. Why? So I have fixed my PC's glitch. It was just a small glitch in my PowerPoint. So the DNA strands will separate when the weak hydrogen bonds break. You know that the DNA strand will separate. I am just creating more space here. They will separate. So my strand here has got A, G, C, and it has got T, C, A. Is it all clear, guys? Yes. So do you see that we don't have any weak hydrogen bonds anymore? Here on this side, we have got T, we have got C, we have got G. And then we have got A, we have got G, we have got T. How? This thing has started again. A, C, A, or A, G, T. I don't know what's wrong with this software today. It's giving problems. This is A, G, T. Let's sleep, sir. No. No, no one is sleeping. So here the weak hydrogen bonds will break. Okay. So why do we otherwise say that the DNA double strand unzips? We otherwise say that the DNA double strand unzips so that you guys understand that when the weak hydrogen bonds break, the strands actually separate from one another. Actually, guys, you can see that these weak hydrogen bonds, they kind of look like a zip. Do you guys imagine it in that way? Yes, sir. Yes, they kind of look like a zip, guys. If you've got any jacket with a zip, when you've closed your zip, imagine the zip as the weak hydrogen bonds that is connecting these two strands together. So now when these weak hydrogen bonds break, it's the same thing as saying that the thing is unzipped. The DNA double strand is unzipped. Okay. Are we getting the sense? Yes, sir. All right. So let's hope this piece is not going to erase everything that we just did right now. Okay, cool. It's promising. All right. So now the next thing, the two strands will separate, of course, after the weak hydrogen bonds, obviously, the strands will separate. That's quite obvious. So one DNA strand, guys, look at this now. Only one DNA strand will serve as a template. Guys, when it comes to DNA replication, we say that how many strands serve as a template to build, to replicate DNA? How many strands serve as a template? Two of them, right? So both the DNA strands during DNA replication, both of them, they serve as a template to form the other DNA strands. But now only one DNA strand will be used. When we say that it serves as a template, it simply means that only one DNA strand will be used to form what? To form mRNA. Are we getting me? Yes. Only one strand will only use one strand to form mRNA. But now how do we form the mRNA? That's the most important thing. We form the mRNA using free RNA nucleotides. Guys, this is the most important thing. When it comes to DNA replication, we form the DNA strands using free DNA nucleotides. You still remember the process, right? We use free DNA nucleotides during DNA replication. So here, if you guys just say using free nucleotides, it's wrong. You won't get the mark. If you just say to form mRNA using free nucleotides from the nucleoplasm, that is absolutely incorrect. You have to specify free RNA nucleotides. Remember the RNA nucleotides, they are different from the DNA nucleotides. What makes them different? Who knows what makes the nucleotides different? Yes, Trev. The RNA have a nitrogenous base, uracil, and then the DNA nucleotides have a nitrogenous base, thiamine. Excellent. You see, the RNA has got a nitrogenous base, uracil, whereas the DNA nucleotide has got a nitrogenous base, thiamine. What else makes the RNA nucleotides and the DNA nucleotides different from one another? What else do you guys remember? Is it all about uracil and thiamine? What else? Yes, Trevor. RNA is only single-stranded, while DNA molecules have two strands. Yes, we are talking about... Okay, you are right when we are talking about the entire molecule, but here we are specific on the nucleotide alone. Just something specific about just the phosphate group, the sugar, as well as the what? As well as the nitrogenous bases. On the nucleotides, what else makes them different, Trev? The RNA have ribose sugar, while the DNA have a deoxyribose sugar. Yes, guys. The RNA nucleotide, it is made up of ribose sugar, but the DNA nucleotide is made up of deoxyribose sugar. So, it's very imperative and very important for you guys to use the term free RNA nucleotide. So, if you guys do not say the type of nucleotide that you are using, you will omit the mark for both the processes, both DNA replication and transcription. All right. So, here we are using free RNA nucleotides because we want to produce mRNA. Actually, guys, transcription, it is the formation of mRNA, and we say that it is formed in the nucleus. Okay. It is formed in the nucleus through a process known as transcription. So, the process we are describing here, we are trying to form mRNA in the nucleus. All right. So, we have to use free RNA nucleotides. So, using the same technique as DNA replication, guys, I repeat, where do we find nucleotides? I'm asking now, where do we find nucleotides? Where do we find nucleotides? Do we just find them floating in the air? Yes, Trev. In the nucleoplasm. Yes, guys, when we did DNA replication, I specified that the nucleoplasm, which is the space that is filled with the fluid in the nucleus, it consists of, or it has got what? It has got free floating, or it has got free DNA and RNA nucleotides. So, in the nucleoplasm, we have got both types of nucleotides, both RNA and DNA nucleotides. So, a nucleotide is just the normal structure, guys. It's a phosphate group. We've got a, what's wrong with this? We've got a phosphate group. We've got a sugar, a type of sugar, depending on the molecule. But in this case, we are doing an RNA. So, we must have the nitrogenous bases. How many nitrogenous bases can we have in RNA? Which ones? We know that is adenine, cytosine, guanine, as well as uracil. So, let's just say this is having a nitrogenous base, which is uracil. So, this is clearly an RNA nucleotide. So, this is your RNA nucleotide that is found inside the nucleoplasm. So, guys, remember that adenine. Now, when it comes to RNA, I told you how the bases pair. Guys, when we introduced RNA, I told you that adenine is complementary to which? Which base is adenine complementary to? Amine. Yes, that's right. Uracil. Uracil, yes, guys. We are talking about the RNA, guys. When it comes to RNA, remember that I told you that it doesn't pair in uracil, okay? So, we have got adenine that is complementary to uracil instead of thymine, okay? Because we are talking about mRNA here, all right? And then cytosine, it is still complementary to guanine, all right? Are we still together? Yes, sir. Yes. Yes, sir. That technique will help you. But how many strands will we use, guys? How many strands will we use? We'll only use one strand. So, guys, remember DNA is double-stranded. So, this is one strand. This is another strand. So, let's just say one of the strands will be useful. But the other one, this one, let's just say we will not use it. This one, don't use it. Only use one. So, here, this is emphasizing that only one strand serves as a template. Only one strand can work as a template. So, what will happen to the other strand? We will see what will happen to it when we see how we form the RNA, okay? Yeah. So, now, at this point, let's just do the pairing. So, obviously, this adenine, it will look for a nucleotide with uracil to pair with, right? So, basically, I will just bring the uracil. So, I will bring the U next to the A. So, now, we have a uracil. So, it means this is a nucleotide coming from the nucleoplasm consisting of the nitrogenous base uracil. Guanine will look for a nucleotide with cytosine as the nitrogenous base. And then cytosine will look for the one with guanine. And then thiamine, guys, thiamine pairs with what? That's the question. Now, we have got thiamine. Yes, it pairs with adenine. Don't say it pairs with uracil. It will be wrong. Because thiamine, it doesn't pair with uracil. Thiamine pairs with adenine. But adenine also pairs with what? With uracil. Now, it will depend on the case where you are. If you are forming RNA, adenine will pair with uracil. But if you are forming DNA, for example, you are doing DNA replication, adenine will bond with what? With thiamine. Yes, Sam? Yes, Sam. Sir, I wanted to ask you also. So, it's possible this new strand is even an error? Well, that is known as a mutation. But we're still going there later on. Don't worry. Yes, it can happen. You see, an error can develop through it. Yeah, all right. So, you guys are understanding when I say that adenine pairs with thiamine and also with uracil. But it depends on what we are forming. In this case, we are forming a certain type of RNA, right? In this case, we are forming mRNA. So, adenine will pair with uracil. But if we are doing DNA replication, adenine pairs with what? With thiamine, if we are forming another DNA strand. So here, since we've got a thiamine on the DNA molecule, to form mRNA, guys, thiamine will still pair with adenine, okay? Because adenine, it is found in RNA as well. So, if you guys are going to tell me, if you guys are going to do this cross pairing, because most of you guys do this mistake and say that thiamine pairs with uracil, this is incorrect. Thiamine does not pair with uracil, okay? Thiamine pairs with adenine, whether it is DNA, whether it is RNA. Because adenine is present in both of them. But adenine can pair with uracil, or it can pair with thiamine, depending on what we are forming. When we did DNA replication, adenine was pairing with thiamine. You still remember that, right? Yes. And then, now, when it is transcription process, adenine pairs with what? With uracil. Because we are forming RNA. We are forming mRNA to be particular. Are we clear? Yes, sir. Please don't make such mistakes. Take your time doing this best pairing. Cytosine is still guanine. Adenine will pair with what, guys? Adenine will pair with what? Uracil. If you say thiamine, you are wrong. Because here, we are trying to form mRNA. So, you cannot be having thiamine in mRNA. And this will form its own strand. So, now, we have got another strand. This strand is mRNA. This one having uracil, cytosine, guanine, adenine, guanine, uracil. So, guys, we have already formed mRNA. Do you see how wonderful it is? We have already formed mRNA. Do you see it, guys? Yes. Yeah. So, this mRNA, what will happen to it? It will actually come out of the nucleus. So, it will separate from the DNA strand. This weak hydrogen bond here, it is so weak. The bond between a... Okay, the bond that we have when we are forming mRNA, it is very weak. So, immediately, when mRNA is done being formed, or it is done being created, or being transcribed, it will eventually move out of the nucleus. Do you all get it, guys? Yes. So, this is your mRNA. I will draw it here. This is your mRNA. It is single-stranded, remember. So, it will have single strand. Don't tell me, guys, that this is double-stranded. No. Don't tell me that because this black strand is from DNA, and this reddish strand is the one that we have formed from using the RNA nucleotides from the nucleoplasm. Are we seeing that? Yes. Okay, so let me just write the bases. So, I'll just start writing here, just for space. We have got U, we have got C. Do you see, guys? I'm writing them exactly as they are here. I'm not guessing them. It's UCG. Do you see them, guys, from this strand, this mRNA? Yes. Yes, it's UCG and AGU. So, it's UCG, AGU. So, the mRNA, this is an mRNA. How do you identify that it's mRNA? There's uracil there. So, this is your mRNA. So, we are done with transcription because we have created, or we have transcribed the mRNA molecule. Are we seeing this, guys? Yes. So, someone asked me, what will happen to the other strand? When the mRNA is done being created, it will eventually move away from this DNA strand, okay? It will move away from this DNA strand in such a way that these DNA strands, the original ones, they will recoil with each other. They will rewind with each other. Actually, they unwinded. So, they will rewind again and form another double helix and just go back to normal. Yes. So, do you see that we have been able to make some mRNA? But after that, these two DNA strands will recoil. They will rewind and become together again, just like before. Do you guys see that? Yes. Is that difficult? No. It's a simple process. Now, I told you guys that when we have got three nitrogenous bases following each other in a DNA molecule, what do we call it? It's a DNA-based triplet, sir. Yes, it's a DNA-based triplet. If we are having three nitrogenous bases following each other in a DNA molecule. All right. But when it comes to mRNA, now we have got mRNA. If we have three nitrogenous bases that are following each other, as in like three nitrogenous bases following each other. We did this last time. What did we say this is known as? Three nitrogenous bases following each other in an mRNA molecule. Known as codons. Okay, so here we're having two codons because we just count, guys. It's literally counting. You count one nitrogenous base, two, and three. So that's one codon. You count again, one nitrogenous base, two, three. That's another codon. So we have got two codons here. So here, these ones, we are going to say that on this mRNA, we have got two codons. But on this DNA strand, guys, we have got two what? We have got two DNA-based triplets. Yes. So I'll just write DNA-based triplet. DNA-based triplet. Are we guys together? Yes. Yeah. So that's how the process finishes up. This is a more formal diagram that they will use. Do you see, guys, what we've described just now? Do you see that at first, our DNA double helix was a double helix structure, but it was unwinded, and then we were able to create some mRNA. Yes, sir? So, sir, this mRNA, if I say it formally, it will be like a DNA molecule. Therefore, the DNA molecule, let's say, it will serve as a union. Well, DNA will just go back to normal. Nothing will happen to it. It is just to create mRNA. Then mRNA must leave the nucleus. It's not coming back again. It will harm once and for all. Okay, sir. Yeah. So you guys can see here. So I'm going to... Ewa, Ewa, Trevor? Sir, so I would like to know during which phase this process occurs. During which phase? Yeah. No, not at all. Transcription itself, it is the stage where mRNA is produced. Okay. Are we together? Yes, sir. All right. So, guys, I want you to look carefully. It's only three minutes. Our two hours has already passed. But because this lesson is a bit fun today, we're still here. I have got three strands here. Can you see the three lines? The three strands that you're having? Strand A, strand B, and strand C. Now I'm going to ask you guys, which strand represents a DNA molecule? Which strands are from the DNA in this case? A and C. A and C, right? So strand A and C, both of them, they are DNA strands. If they say give a reason for your answer, you have to look out for things such as the presence of thymine. Do we get each other? Yes. And then what about strand B? What is strand B? Just as we have created it or transcribed it. So if you guys are able to see that, you guys can be able to see. And you guys can be able to see how many codons we have. You guys can be able to see how many base triplets we have. You just need to count three nitrogenous bases that are following each other. Are we together? Yes. You simply compute the process and say mRNA is complementary to DNA. This is just telling you that the nitrogenous bases are corresponding to one another. For example, if we... You say it's understood. Yeah, this one is pretty easy to understand. For example, here the adenine is matching with U. G is matching with C. So you can see that here we are having complementary strand and mRNA complementary. Are we fine? Are we still fine? Yes. All right. Awesome, guys. So now today we are done. For today we are done. I didn't even think that we would reach this far. But it looks like we did quite a lot. I want you guys to revise what we've done today. I hope that you were able to collect notes. If you were not, they were their videos. All right. If my Google Drive storage runs out, I'll put them on YouTube also for everyone to see. All right. So you guys study the videos, study the notes. Make sure that you understand transcription to the core. Don't just cram the process. Understand how it works. When we come back next time, we must be able to do art. We must be able to do a translation. So since we've got less than one minute, guys, let's make a quick prayer. I will pray quick. All right. Let's close our eyes. Amen.