Life Processes Complete Chapter🔥| CLASS 10 Science | NCERT Covered| Prashant Kirad

Jali is called fire, bhuji is called ash. And the one who makes complicated subjects like science easy is called Prashant Kiran. So hi everyone, I am your very own Prashant Bhaiya and I have brought a dangerously amazing one-shot of Life Process. I know, friend, you are having a lot of trouble with this chapter, like, how will we understand this human heart? There are so many names, it's hard to understand. Nephron is hard to understand. Respiration is hard to understand, aerobic, anaerobic. Oh brother, today I will teach you, give you tricks, and along with that, the most important questions, those questions that can be repeated in your paper, all of that will be available in this single one-shot. Okay? So get ready because Ishant Bhaiya has arrived. And why to fear when PK Bhaiya is here. So remember, there is nothing to fear. How is the Josh meter? Tell me that first. What is the energy level? What is the Josh meter? Energy is absolutely high. When your master is full of energy here, how can you be slow? Huh? What kind of energy are you? Sitting low. We don't have to sit low. We have to stay with high energy. Okay? So let's start this chapter. First of all, its heading is Life Process. Now see, Biology is a very beautiful subject. Why? People say Biology is a very beautiful subject. Why? Because see, Math people have gone to find 'x', Chemistry people are setting up their chemistry, and Physics people are sadly searching for Newton Baba, and we Biology people, we are learning about life. And that's why this chapter is named Life Processes. What does Life Processes mean? Process means work. Life means life. That is, all those processes that are essential for living life. That is, important. That is, what are Life Processes? All those functions that are basic and essential activities performed by a living organism to sustain and maintain life. That is, everything needed to stay alive is what for me? It is life process for me. Now you will say, brother, using a phone is also a life process. We can't live without it. See, maybe it is a life process for you. Because now you are addicted. But come out of that phone addiction because we are studying. Okay? But using a phone is not a life process. If they ask in the paper and you write it. Yes, it is for us. PK Bhaiya said so. No, no, Life Processes are basically of four types. And this whole chapter is about them. First is Nutrition. Eating food. Yes. What is the second? The second is Respiration. Producing energy. Next is Transportation. Transporting everywhere. And last comes Excretion. You know that. So basically there are four types. Nutrition, Respiration, Transportation, Excretion. We will study all of them in detail, one by one. Come. Let's start with Nutrition first. Okay? Now what is Nutrition? Is eating food nutrition? I said, no, you've got it wrong, brother. Eating food is not nutrition. Eating food and obtaining energy, that is, taking energy from it. That whole process is called nutrition. Okay? Now what do we eat in nutrition? Like you eat carbohydrates, you eat fat, besides that you eat protein, vitamins, minerals. Mainly you eat fat. Burgers, pizzas, I know everything. Right? That's what you're eating. Fat and all. No problem, child. So what is nutrition? Remember. The process by which a living organism obtains and utilizes. This is a very important line, child. Utilize means to make use of that food, to utilize it. Right? That is also included in nutrition. It is called Nutrition. Food gives us energy, growth, and development. What does food give? Energy, growth, development. Everyone knows. If you don't eat, you will die, friend. Obvious. No, brother, we won't die. You will die, friend. Don't eat for three, four, five days. You will be in a bad state by the seventh or eighth day. Okay? Yes, so you have to eat food. Okay? There are four components of food. I have told you. Carbohydrates, proteins, fats. Mainly we eat these. Brother, I was watching the lecture, and my mouth started watering. Now I feel like eating a burger. No problem, child. I am also hungry, you are also hungry. We will both study. Now see, there are two types of nutrition. Autotrophic and Heterotrophic. Auto means not that auto, auto means by itself. That is, this type of nutrition is where organisms make their own food. Now you will say, brother, does my mother do autotrophic nutrition? Because my mother makes her own food. I said, you will get hit. No, foolish child, I say it lovingly, foolish child. Okay? Don't feel bad. You are my foolish child. Okay? So, foolish child, it's not like that. Autotrophic nutrition is a type of nutrition where yes, organisms make food themselves. But from inorganic substances like oxygen, carbon dioxide, water. See, the food made in your house is from vegetables. What are vegetables? Plants. So what is autotrophic nutrition? Mode of nutrition in which organisms prepare their own food using simple inorganic substances like CO2, water in the presence of sunlight and chlorophyll. Okay? Now see, child, autotrophs are of two types. And understand the examples of both these types. First is what? One autotroph is what we call photosynthesis, which plants do. You must have studied this in lower classes. What are you saying? You didn't study in lower classes. You were having fun with friends. No problem. No problem. Okay? Photosynthesis is done by green plants. Okay? Plants that have chlorophyll. We will talk about this in detail. For now, just understand that photosynthesis is a type of autotrophic nutrition. Besides this, who else does autotrophic nutrition besides plants? So some algae do. Some algae do. Some cyanobacteria also do photosynthesis. Besides that, there is chemosynthesis. Chemosynthesis is a process in which organisms make their own food, but with the help of some chemicals. Okay, child? So remember, type of autotrophic nutrition in which organism prepares its own food by utilizing chemical energy. Now its example is very important. It has been asked many times. The example is purple sulfur bacteria. Very important. Asked many times. Okay? I will keep pointing out important questions. Don't worry. Don't stress. Where will you get the notes? You can join Telegram, or I will put them in the description. Okay? So, very good. Understood? Okay. Now, what was this heterotrophic, brother? Heterotrophic, like you, all of us. We are dependent on someone else. We are eating plants. So we are dependent on plants for food. So that is heterotrophic nutrition. The mode of nutrition in which organisms depend on other organisms for their food because they cannot prepare their own food. All animals are dependent on plants. See, how important plants are, friend. We feel that trees and plants are not important. Brother, they are very important. Without them, what is our food? We cannot make our own food, friend. If there are no plants, how will the world run? Now, let me tell you the types of heterotrophic nutrition first. Heterotrophic nutrition is of three types. One is holozoic. Now, don't get scared by hearing the name. I know you have come to 10th grade, and seeing Biology, you say, brother, what is this being taught? Holozoic. Wait. One is holozoic, one is saprophytic, and one is parasitic. Understand. What is holozoic nutrition? Holozoic. Soic. What do you understand from holozoic? Something big. That is, we are also big. So holozoic nutrition is what we follow. What do we do? We pick up a big piece of food, put it in our mouth, and eat it. That's what you do, right? And when you want to eat a burger, you do this, right? Right? Does this happen with you too? When your friend brings Maggi in their tiffin box at school, the tiffin box opens before recess, and all of it is gobbled up quickly. Right? Whoever eats faster, eats more. Right? Yes. So, what is holozoic? Animal takes the solid food which is broken down inside the body. What is the example? We are animals. And there is another organism, a unicellular organism, called Amoeba. Amoeba. Okay? Now let's study what parasitic is. What is parasitic nutrition? Parasite. Do you understand parasite? You must have seen the movie Parasite. Right? So, see, this parasitic nutrition, what is it? Understand carefully. Parasite means something that is on someone else and draws its food from it. Like, for example, in childhood, they used to say that you got lice in your hair. What happened in your hair? Lice got in your hair. Didn't they say that? Tell me quickly. Didn't they say that you got lice in your hair? What did lice do in your hair? They took your blood from your body. That is, what is parasitic nutrition? Type of nutrition in which organism lives in or outside another organism. That is, it is in our hair. So it is on us. Okay? It is on us, and what are we to it? We are the host for it. Host means from whom it obtains its nutrition. Okay? And derive nutrition from it. Remember, in parasitic nutrition, the parasite does not kill the other. It just keeps obtaining its food from it. Remember the example. It's the best example. Cuscuta. Cuscuta. What is Cuscuta? It is a type of plant, and I am telling you to remember it because it is the only plant that follows parasitic nutrition. The only plant like this is Cuscuta. Right? Besides that, there are ticks, leeches. Do you know leeches, the ones that suck blood? Yes, very good, brother, they also suck my blood. No problem. No problem, child. Okay? Yes. You are the one who is crazy. Come. Let's talk about saprophytic nutrition. First, we understood holozoic and parasitic. Now, this is the worst, saprophytic. Saprophytic is in between. What does it do? It eats dead and decaying organisms. But there is one thing: it digests the food outside. It digests the food outside. It releases some chemicals that digest the food outside. And then it directly absorbs the nutrients. That is, in this, organisms feed on dead and decaying matter. Remember, it digests outside and then absorbs. Its example is fungi. And a very big example is what? Mushroom. Write it down, friend. A very big example is what? Mushroom. The mushroom you eat also follows saprophytic nutrition. It eats dead and decaying matter. Did you understand this? Say yes. Very good, if understood, let's move forward. Did you understand this? Now let's look at some questions that have been asked from here. Come, important question. Look at 2017, 2020, 2021. Look, friend, which of the following organisms exhibits saprophytic? Saprophytic. See, holozoic, parasitic, the one in between. Yes, saprophytic. So who does the one in between among these? I just told you, mushroom. Who eats mushrooms among you? Do you eat mushrooms? Mushroom does saprophytic. It eats dead and decaying matter. Remember this. Which of the following organisms shows parasitic mode? Parasitic. Parasite. Parasite. Who among these seems like a parasite? Cuscuta. Cuscuta. Remember, child, remember. What's next? Such big questions are coming nowadays. They give a big paragraph and ask small questions. Like, an organism was discovered that lacks chlorophyll. It doesn't have chlorophyll. It survives by penetrating the tissues of another living organism from which it absorbs nutrients. However, it neither kills the host. That is, it doesn't kill the other. It just absorbs. Oh, you know this. You know this. The last one, parasite. Parasite. Very good. That means it is parasitic. Parasitic. This is its name. Okay, friend? Parasitic. Remove autotroph from here, friend. Remove this from here. Okay? Not this, friend. Not this. Okay? Remove this from here. What is it? It is a type of parasitic nutrition. That is, it is obtaining from the other. See, it's not killing the other. It shows specialty by infecting only particular plant species. Okay? Understood? Very good. Let's go, friend. Now let's move to the next. In autotrophic nutrition, I told you I would talk about photosynthesis in detail. And children think, brother, photosynthesis is so easy in 10th grade, who will ask? They do ask, and they also ask the reaction. How does photosynthesis happen? There is a plant. Green leaves of the plant. I have even brought a plant for you. Where is my plant? Friend, where is my plant, friend? Wait, friend. Here is the plant, friends. Presenting the plant for you. Huh? Now no one will say it's a fake plant. So see, brother, we have even grown flowers on this plant. But this green part, what is this green part, friends? So this green part is chlorophyll. That is, photosynthesis happens because of this green pigment. Right? This poor thing can't do it. It's fake, poor thing. Right? So it's fake. What can we do? But photosynthesis happens because of chlorophyll. Okay, what else is needed for photosynthesis? Understand. First is chlorophyll. Second is sunlight. Third is carbon dioxide. And fourth is water, H2O. Very important. Okay? So first, look at the reaction, and this reaction must be remembered. Don't forget this even by mistake. What is the reaction? What things combine? 6 CO2 + 12H2O. Now there are two things. Chlorophyll, sunlight. Right? Both of them come. And then what is formed? Food. And what is food? Glucose. Glucose is food. Remember the formula for glucose. C6H12O6. So glucose is formed, and along with it, oxygen gas is released, and H2O gas is released. Not H2O gas, H2O water is being released. Okay? Did you understand everything? Very good. Okay? So what are the raw materials for photosynthesis? Four: CO2, say with me, CO2, H2O, and what else? Sunlight and chlorophyll. Very good, friends. Okay? So remember, chloroplast is the site of photosynthesis, which are green pigmented. That is, there is something inside it, which I am calling the green color, what is it? Chlorophyll. That is, it is happening because of chlorophyll. Okay? Very good. Now remember the events that happen in photosynthesis. So the first event is absorption of light energy. Let's understand this story in detail. First, what will happen? I have a leaf, a leaf. A green leaf. It will call sunlight to itself. Sunlight, come to me, come, come. Now sunlight has come to it. So what did it do? As soon as it called sunlight to itself, it trapped it. Trapped it in its net. It trapped all the energy. Now what did it do? It broke down that light energy. Second step: conversion of light energy into chemical energy. It converted it into chemical energy. See, something is happening with light. Now with the help of that chemical energy, what did it do? It broke down the water molecules into hydrogen and oxygen. Broke it into hydrogen and oxygen. Two tasks are done. Now the third step, and the most important step. Now this CO2, this carbon dioxide gas, is converted into what? Carbohydrate. Carbohydrate means glucose energy. So it is converted into energy. So there are three steps. First, it called it to itself, trapped it. Converted it into chemical energy. Broke water, and after that, what did it do? Converted CO2 into carbohydrate. Isn't it very simple? Oh, it's simple. Does this seem difficult? Does this really seem difficult to you? Who is saying it seems so difficult? Oh, friend, it's so easy. What are you saying, friends? Okay? Okay. Now remember one more thing, this is a very important note: plants store glucose in the form of starch. That is, plants store it in the form of starch. And animals, that glucose, animals store it in the form of what? Glycogen. In what form? Glycogen. Okay, friend? They store glucose in the form of glycogen. And they store it in the form of starch. It has been asked in MCQs. Remember. I will keep telling you all the important questions. So let's talk about how this gas exchange happens. This CO2 comes in. Oxygen goes out. How does it happen? This is done by stomata. What are stomata? They are a type of pore. Pore means a hole. Now, these holes, for example, let me explain. Suppose, suppose, see, there are two cells here like this. These two cells are shaped like this, like this. We call them guard cells. Guard means they are guards. Okay? Now, what do guard cells do? As soon as water comes into the guard cells, the guard cells open. When water comes, they open, so the stoma opens. And when water goes, the guard cells close. Water comes, opens; water goes, closes. Okay? So who controls the stomata? This is its diagram, child. The diagram has been asked many times. Remember the diagram. These bean-like structures you see are guard cells. As soon as water comes into them, child, they open the stomatal pore. And as soon as water goes, they close the stomatal pore. Okay? Okay, remember this diagram. Inside this, what you see as green is nothing. It is chlorophyll. Chloroplast. Very good. Okay? Okay, understood this? Everything runs with water. Okay, what are the functions of stomata? First, you know, gas exchange. There is one more function. Do you know what it is? Sometimes there is too much excess water in the plant. Too much water. So this water comes to the leaf. And from the leaf, water goes out. And that process is called transpiration. Perhaps you have studied this in lower classes, child. One function is gas exchange. The second is to lose a large amount of water vapor during transpiration. That is, transpiration is a process in which excess water goes out with the help of leaves. Have you ever seen, the leaves of trees look a little wet due to transpiration. So stomata have two functions. One is to cause transpiration, and the other is to exchange gases. Okay? Did you understand this? Very good. Okay, let's look at some observations for desert plants. Now, desert plants are completely different. This was a normal plant. Now, desert plants have a big problem. A crisis. What is it? That, friend, if there is so much sun during the day. If, brother, it opens its stomata during the day, and the sun is shining, all the water will go away. Poor thing will die. So it plays a game. What does it do, child? Understand carefully. Stomata opens at night. That is, it opens stomata at night and quickly calls, CO2, CO2, come, come, come, come, come. And it keeps the CO2 inside. Okay? So, it keeps CO2 inside. And during the day, what does it do? It keeps stomata closed. But it can do photosynthesis. Because light comes during the day. So photosynthesis will only happen during the day. It cannot happen at night. Okay? So stomata close during the day. And then what happens? CO2 taken at night is used for photosynthesis. That is, CO2 is trapped at night, and photosynthesis happens during the day. Smart, the desert plant. Smart, child, smart. It turned out to be smarter than you. I thought you were the smartest, child. But this turned out to be smarter than you. Let's ask some questions. What are stomata? Such questions have been asked. What are stomata? Do you know? What are they? Tiny pores present mostly on the underside of the leaf. On the lower side of the leaf, there are tiny pores, which we call stomata, child. Very good. Next question: Where are they located in the plant? They are located in the leaves. Okay? State two functions of stomata. Tell me two functions of stomata, friend. Transpiration and gas exchange. Also explain how their opening and closing is regulated. Who controls them? Guard cells. Water comes, opens. Water goes, closes. Very good. Let's look at the next question. This is an activity. This is not a question. This is an activity that many teachers don't do, but I have brought every activity, everything for you, child. We study everything in detail. Okay? And that too in less time. That's the specialty of PK Bhaiya. Okay? Yes, I have flexed. Okay, see what happens inside. There is an activity in NCERT. In this, there is a salt called KOH, that is, potassium hydroxide. It is kept. Now remember, what does this salt do? It absorbs CO2. That is, it pulls carbon dioxide and eliminates carbon dioxide from nature. That is, carbon dioxide is finished in this place. Now what happens? This pot is kept inside this jar. This plant is kept. Sunlight is coming, but it cannot do photosynthesis. Why can't it do it? Because KOH is kept. It absorbed CO2. And you know, if photosynthesis is to be done, four raw materials are important. If any one of those four is missing, there will be a problem, a crisis. And one brother is missing. Which brother is missing? CO2 is missing. Now CO2 is missing, so in this case, photosynthesis will never happen. Remember this activity. Sometimes questions come asking what KOH does. So KOH absorbs CO2. Okay, friend. Very good. Now let's come to the next topic. Nutrition in Amoeba. All about plants is finished. Now we are talking about holozoic nutrition, which we do. Besides us, there was one more creature. Who? Amoeba. Besides Amoeba, there is another creature called Paramecium. So now we will talk about Amoeba. Just a minute, let me drink some water. So let's study Amoeba. Then we will study its other friend, whose name is Paramecium. Okay, have you ever noticed in friendship, when there are two friends, they talk very nicely. There are two friends, there is a lot of fun. There is laughter and jokes. But when there are three friends, one person is continuously being insulted. One is being made fun of. Two people are laughing. Right? I also used to have two friends. Right? And I had two friends. Right? My two friends, neither rich nor poor, neither rich nor poor, I had two friends, both of them pigs. We used to say this to each other. It's from my time, meaning I'm not much older than you, but okay. Okay? Come on, friend, let's talk about Amoeba. What is in Amoeba? It is a five-step process, and every holozoic nutrition has these five steps. What is the first step? Ingestion. Ingestion. Ingestion means taking food inside. Taking food inside. So first, remember, what is ingestion? Amoeba surrounds the food particle using finger-like projections called pseudopodia. Pseudopodia. It has hands, what are they called? Pseudopodia. Okay? It has hands, which we call pseudopodia. With their help, it takes food inside. Suppose there is food. I took the food inside like this. So what did I do? I ingested. The next process is digestion. What is digestion? Enzymes are secreted into food vacuoles, breaking down the food into simple. That is, that food is broken down. Its digestion is done. The next process is absorption. Now, the digested food, after digesting it, it also has to be absorbed by the Amoeba. So that is called absorption. Digested food is absorbed into the cytoplasm and used for energy. Next comes assimilation. Now, this assimilation is very important because children don't understand it. They understand up to absorption. They don't understand assimilation. See, what is assimilation? I have taken energy. Now, utilizing that energy, that is, moving here and there, moving around a bit. Because of that, energy is being used. So that process is called assimilation. That is, absorbed nutrients are utilized in various life processes. And the last one comes, egestion. The final egestion. Egestion. Egestion means removing undigested food. Remember ingestion, digestion, absorption, assimilation, and egestion, removing outside. Now this diagram has also been asked many times, child. Remember this diagram. First, there is an Amoeba. Where did this cookie-like Amoeba come from, friend? Does it look like a cookie? A tasty cookie, right? So food particle, this Amoeba, what is this? Pseudopodia. With the help of pseudopodia, it takes it inside. Okay? So now what did it do? It took it inside. After taking it inside, it puts it in its food vacuole, and digestion starts. So here you can see digestion has started. Now, as soon as digestion starts, what happens here? Absorption and assimilation happened. Right? Absorption, absorbed energy, and used it in all life processes. And what is the last step? The last step is to remove it. The waste, the waste is removed. We call it egestion. So remember these five steps. If you remember these five steps, there won't be much difficulty. Okay? Now it has another brother, whose name is Paramecium. See, the processes for both Paramecium and Amoeba are the same. Only one thing is different. First step, ingestion. What did Amoeba do? It ate food with the help of pseudopodia. What does this one do, child? It has hair-like structures. We call them cilia. Cilia. This diagram is also important. Not that important, but okay. You can see these hair-like projections. We call them cilia. Child, this is Paramecium. These are cilia. So what does it do? With the help of cilia, it brings food near its mouth and puts it inside the mouth. Right? It brings it near the mouth and puts it right inside the mouth. So, only ingestion is different. What is in Paramecium? Cilia. That's all. All other things are exactly the same. Digestion, absorption, assimilation, and what is the last one? Egestion. Exactly the same. It's Amoeba's brother. That's why I said brother at the beginning. Okay, friend, very good. Okay, now a question has been asked many times. Differentiate between Amoeba and Paramecium based on the mode of nutrition. What is the mode of nutrition for both of them? It's the same, child. Holozoic nutrition. Holozoic nutrition. Same. Next is locomotion. Locomotion means how they move. So Amoeba moves with the help of pseudopodia. And with what does this one move? Paramecium moves with cilia. Hair-like structures. Very good, child. Okay, very good. Now finally, it's the turn of humans, friends. Now see, humans also do holozoic nutrition. So humans will also follow five steps. The same five steps: ingestion, digestion, absorption, assimilation, egestion. Now you've remembered. Yes. Okay? Now see, it's the same five steps. Now, where does it start? Food. This diagram has been asked. It has been asked. It has been asked many times, brother. With great sadness, I have to say this diagram. It has been asked. So remember it. See, it starts with eating food. Now, brother, if I have to eat food, how will I eat it? I will eat it with my mouth. I will pick it up with my hand and put it in my mouth. That's what I will do. So that process is called ingestion. Okay? Now, where does the digestion of food start? People think food is digested in the stomach. No, it starts in the mouth. Yes, it starts in the mouth. Let's see one by one what happens. Tell me an example. What do you want to eat? What do you want to eat today? Whatever you say, we will imagine eating it. For example, I imagine. Burger, pizza, that's what you want to eat, right? Momos, noodles, ah ah. No, child, whatever you wish and you get it. Has that ever happened? It will happen today. So today we will eat bottle gourd curry, friends. Let's have a big round of applause and get ready to eat bottle gourd curry. So now the bottle gourd curry has arrived, and you and I have eaten it. Okay? Okay. No, no, it's good. Bottle gourd curry is good. Healthy, healthy, healthy. Okay? So now we have eaten bottle gourd curry. So see, child, first what happens? First, it comes into our mouth. Okay? In the mouth, and what happens in the mouth? First, the food is crushed. Not that crush. The food is crushed. Okay? So first, the food will be crushed. Then, there is a salivary gland inside our mouth, which releases saliva. You know what saliva is. Okay? So saliva is released. Now the main work starts. See, our tongue mixes the saliva with the food. Now, what happens is that there is an enzyme in the saliva. Enzyme. And remember the name of that enzyme, it is salivary amylase. Now, what does this salivary amylase do? It takes complex sugar, that is, starch, that is, starch. What does it do to starch? It converts it into maltose. Maltose. Remember, this is a simple sugar. So it converts this complex sugar into a simple sugar, which is maltose. Who is doing it? Salivary amylase. Salivary amylase. Very good. Now the food goes down. Esophagus, that is, food pipe. How does the food pipe push food down? There is a movement. Not like this, like this, like this. It's not like that. Contraction. There is a slight movement like this. Right? So that movement is called peristaltic movement. So food is pushed down through a peristaltic movement. What happens? Rhythmic contraction of muscles in the wall of the alimentary canal. What is the alimentary canal? I'm coming to that. Just wait. Okay? So, in the esophagus, there is a movement of contraction and expansion. We call it peristaltic movement. Remember. Okay, friend? Where had the story reached, child? The story reached here, ding ding ding ding. Now comes, brother, the stomach. Now see, what is the shape of the stomach first? It looks J-shaped. J-shaped. Okay? Now, as soon as food enters the stomach, three brothers were sitting in the stomach. All three were brothers. I asked, who were the three brothers? So first comes one brother. Who was the elder brother. The elder brother's name was HCl, hydrochloric acid. So let's study them one by one. Okay, let's start one by one. Now there were three brothers in the stomach. All three were brothers. First is what? HCl. Actually, see, the stomach releases gastric juice. Gastric juice. And all these three things are inside that gastric juice. Okay? So the first brother, the elder brother, HCl. What does HCl do? Creates an acidic medium. That is, it kills all the germs, bacteria, that you eat in burgers, pizzas. All those dirty hands that the golgappa seller touched, gone. Tata, bye-bye. Goodbye. Right? It has one more function. We will talk about that later. Okay? First, it provided an acidic medium. Next comes. The second brother comes, mucus. This is the second brother. What does brother mucus do? It protects from the elder brother. Now see, if there is HCl in the stomach, the stomach wall can get burnt. So what does mucus do? Mucus forms a protective inner lining inside the stomach, so that your stomach doesn't burn and is saved. Okay? Next comes the third brother, pepsin. Pepsin. What is P? Protein. That is, its function is protein digestion. Okay? Now see, that elder brother, with the help of his younger brother.

It does. Because pepsin can only work in an acidic environment. And who is providing the acidic environment? HCl is providing it. This is why I said HCl has another function: to help pepsin's action. Meaning, who is helping pepsin do its job? HCl is helping. Okay? Now, tell me something, have you ever had acidity? Why does acidity happen? Acidity happens sometimes because this balance, you know, between HCl and mucus, the level of HCl increases. And when the level of HCl increases and there is less mucus, mucus is thin. Mucus is a lining on the wall of your stomach. So, you start feeling a burning sensation in your stomach, a strange feeling. Oh brother, why is this burning happening inside the stomach? It happens for this very reason, son. When the levels get disturbed, the levels of everything get disturbed, okay? The levels of HCl and mucus change. Okay, now it moves down. Now the food was going down. Now the food had to go further, towards the small intestine. Let me give the small intestine a nickname: "Chhota Don" (Little Don). Why? Because "chhota" (small) is in its name. Otherwise, it's not small. You know? It's just small in name. But it's a "Don," son, a "Chhota Don." Why? Because it's 7 meters long. Do you know how long 7 meters is? It's 7 meters long, man. It's just small in name. Its tasks are not small. Okay? Now it was going along the way. The food was going. The food had to go into the small intestine. Just then, two goons enter. Bring on the goons, friends. So, here come, ding ding ding, two goons. The first goon arrives and the goon says, "Yes, food, where are you going? Where are you headed?" So the food said, "Oh brother, I'm going there, towards the small intestine." So both goons said, "Let us help a little too." Who were the two goons? If you look closely, son, one goon is the liver, and the other is the small pancreas. See this? This is the pancreas, and this is the liver. Okay? Now what happens? The food was going, and two goons arrived. First, the liver comes. The liver says, "Let me help a little first." So, what did the liver have? The liver has a bladder, a storage, which we call the gall bladder. Inside the gall bladder, it stores a juice. This is the gall bladder. It stores a juice which we call bile juice. Now, this bile juice does two things. What does it do? Let's read about it in detail. Come. So, first, the liver comes. There is bile juice in the liver. Two functions of bile juice. Make food alkaline. Alkaline means basic. See, the food was acidic in the stomach due to HCl. It became basic, alkaline. Okay? Another function it has is emulsification of fat. What is emulsification of fat? What is emulsification of fat? Fats have large globules. Breaking them down into small ones. Okay? Breaking into small droplets, or we can say, what it does is, it breaks down the large globules into small globules. Okay? It emulsifies, it breaks down. Two tasks done. The first goon is happy that he also helped the food a little. Now, you know what happened? The ego of the second goon came into play. Now he said, "Huh? What did you do? You did two things. Man, now I have to do three things." It became a matter of ego, otherwise, his aura won't be more than mine. So the second goon said, "No, man, I have to do three things, man. Three tasks." So the second goon was, son, the pancreas, which I also showed you in the image earlier. So, what does the pancreas do? The pancreas releases a juice. Pancreatic juice. And it contains three enzymes. It has three enzymes. I told you, he did two, so this one will do three. He's also a goon, right? He'll do more work. Okay? So it released three enzymes in the pancreatic juice. The first enzyme was trypsin. Trypsin. "P" is coming in "trip." P means it will digest protein. Now you'll say, "Brother, pepsin also digests protein." Yes, pepsin does, and trypsin also does. Next is lipase. The fat you eat, who will digest it? Lipase will. And next comes pancreatic amylase. Hey, where did we hear the word amylase? We heard it as salivary amylase. Here it is pancreatic amylase. So, the function of amylase is the same. Here too, it will help in the digestion of starch, meaning in the digestion of carbohydrates. Okay? It will be helping in the digestion of carbohydrates. The first goon, two tasks. What did he do? Released bile juice. What did bile juice do? Two tasks: emulsification of fat and making the food basic, alkaline. What did the second goon do? Three tasks. Released one juice. Three things: trypsin, P means protein, lipase, fat, and amylase. Amylase's job is the same, breaking down carbohydrates. Okay? Now, what happened here? Here, both goons became happy, and then the food went down to the small intestine. Right? Food goes into the small intestine, so this is the final, son, the small intestine. The final digestion takes place in the small intestine, at this place. The final digestion happens right here. Okay? And what is finally formed from the final digestion? You remember that. The proteins you ate were converted into amino acids. Okay, man? The carbohydrates you ate were converted into glucose. And the fats from the burgers and pizzas you ate were converted into your fatty acids and glycerol. These three things have finally been formed and are with you, friends. Very good. So, did we understand all these things, son? Tell me quickly. Done? Done. Now, what is the job of this "Chhota Don"? The small intestine. Yes, digestion happened here, but that's not its only job. It's a "Chhota Don." It has another job. Now, what does it do, son? It has another job, which is absorption of food. Digestion is done. What was the next step? Absorption. So, it has some finger-like projections, son, which we call villi. Meaning, imagine this is the wall of the small intestine, and from it, there are finger-like projections. Finger-like projections, which we call villi. What do we call them? Villi. Okay? So, what is it? Absorption of food in the small intestine. What are villi? Finger-like projections. In the inner wall of the small intestine. Okay? It's in the inner wall. Finger-like projections. Now, why does it have finger-like projections? Do you know its job? This absorbed food, it now, you know, absorbs this digested food and sends it into the blood. This is its job. So, it has many blood vessels. There are blood vessels like this. So, what does it do? It pulls the food and throws it into the blood. Okay? So, its main job is? Its main job is absorption. Besides that, why does it have finger-like projections? Because they increase the surface area for absorption. Now, why are these finger-like projections finger-like? You must have asked yourself this question. Because these finger-like projections increase the surface area, and more food can be absorbed. Okay? Next thing, rich blood supply helps transport absorbed nutrients into all body cells. Because it has many blood vessels. So, they absorb the food. Okay? Nutrients are used for energy, growth, and repair. You already know that. Okay? So, here, absorption also happened. Ding ding ding. Who did it? Villi. Very important. Now comes the large intestine. Now, its name is "large." Its tasks are not large, man. What does it do? I'll show you. Here is the large intestine. This big one. What does this large intestine do? The undigested food will go here. And from the undigested food, what will it do? It will pull out the water. It will pull out the water. And then this waste, the absolute waste, you can see here, the anus. Through the anus, it excretes the waste downwards, which you already know. Okay? So, what does the anus do at the end? The job of the large intestine is to absorb water from the undigested food. And what does the anus do? The anus does egestion, meaning removal of undigested food. Okay? Who controls this? There is a muscle, the anal sphincter muscle. It controls it. Very good. Did you understand this? Now, a question is asked repeatedly in exams: why is the small intestine of herbivores, like cows, buffaloes, etc., larger compared to ours? Why this discrimination? This discrimination is because they have to eat plants. The cell walls of plants are made of cellulose, if you remember. Okay? Now, digesting cellulose takes time. Their digestion cannot happen quickly. So, because digestion takes place, that is why their small intestine is larger. Okay? Which answer I have also written here for you. Okay? Very good. So, this is your entire story. Now, let's do some questions with the help of which things will become clearer to you. Quickly tell me the answer. Oh, this is very simple. What's the problem here, man? See what's inside. Which enzyme is secreted in the mouth and what does it digest? Which enzyme comes from the mouth? Oh, man, amylase. What does it do? It breaks down complex sugars, breaks down starch into maltose. Very good. Important, man. Yes, it starts from the mouth. That saliva that comes from your mouth when your mother cooks delicious food. Yes. Okay, have you ever noticed that when you come home from anywhere outside, the first thing we do is? The first thing we do is look for our mother. Where is Mom? Where is Mom? Where is Mom? We ask everyone, "Where is Mom? Where is Mom?" Then if Mom is somewhere around, we find Mom. Mom says, "Yes, what is it?" Nothing. We just need Mom. You know? We just need to see where Mom is. What is she doing? That's all. We don't need anything from Mom. So, we need Mom. Have you seen this? I do it a lot. I still do it. Okay? So, let's look at the next question. In the human alimentary canal, the specific enzyme juice secreted in the location. See, three locations are given in the diagram. The first is location number one. This is the mouth. What happens in the mouth? Salivary amylase. The second location is this. What was this, son? Liver. What did the liver do? The liver secreted bile juice. This is the pancreas. The pancreas secreted three enzymes. So, now match the options. First will be amylase. Amylase. Second will be bile juice, and third, trypsin. Very good. So, the answer is B. Questions like these also come. Let's look at the next question. In human beings, when the process of digestion is completed, the protein, carbohydrate, and fat are broken down into what? Proteins are broken down into amino acids. Carbohydrates are broken down into glucose. And fats are broken down into what? Fatty acids and glycerol. So, option number B. Okay, man, next. This is a theoretical question. And you already know this. State the role of the following: Hydrochloric acid, bile juice, and pepsin. I don't need to tell you, man. What does hydrochloric acid do? Two things. Kills germs. Provides an acidic environment so that pepsin can work. What does pepsin do? Breaks down protein. What does bile juice do? Two things. Bile juice was secreted by the liver. Two things: emulsification of fat and making the food alkaline, basic. Yes, very good. Remember the story. The story of the two goons. This is very important. This has been asked repeatedly in exams. Important. What are villi? Finger-like projections present in the small intestine. Why are they located in the human body? Why are they there? What is their job? To absorb, to take digested food to the blood. How do they help in absorption of food? So, you have to tell how they help. So, one, they increase the surface area. Because they are finger-like projections, right? And second, what do they do? They have many blood vessels inside. So, they directly put the food, I mean, the digested food, into the blood. Okay? Very good. One last question. Complete the following chart. You just have to complete this chart. This is your homework. You will tell me this yourself in the comments. We are talking about gastric glands. Gastric glands secrete three things. What do A, B, and C do? What are gastric glands? Stomach. Stomach? Three, man, all three. So, this is your homework. Okay, friends, let's move on to the next topic, which is breathing or respiration. See, the next thing is respiration, because the next life process is respiration, friends. But, but understand carefully. Breathing and respiration are different. What is breathing? What is respiration? Respiration is using the oxygen from this breath we took to produce energy. Meaning, we are breathing, but our cells are respiring. Every cell respires. If you remember, you will remember one line from the ninth grade. Mitochondria is the powerhouse of the cell. Right? Anyone will ask, "Brother, why is mitochondria the powerhouse of the cell?" Right? That comes, that comes. I also had a habit in school, you know, teachers thought I wouldn't be good at studies because I sat at the back bench. So, I used to sit at the back bench, having fun with friends, but I liked science and stuff, so my marks were good. So, once, the teacher saw me and called me to the board to solve something. Now the teacher thought I wouldn't know. I went, picked up chalk, wrote the entire answer on the board, and turned around. The sir said, "You're okay at studies, but you joke around too much." So, man, backbenchers also have their moments. See, backbenchers also have their moments. Okay? Yes. So, look, what is the difference between breathing and respiration? First, understand this difference. Breathing is a type of physical process: inhaling, exhaling. Inhalation is taking a breath in, exhalation is breathing out. And respiration is a biochemical process. Meaning, your cells do it, son. It's a chemical process. Breathing doesn't have any enzymes, but respiration has enzymes because energy is produced. And in what form is energy produced? In the form of ATP. Remember, powerhouse of the cell, mitochondria. Yes. Okay? What happens in breathing? Only your lungs work in breathing. Lungs. Whereas in respiration, every cell works. No energy is released in breathing. Whereas energy is released in respiration in the form of ATP. It's written here too. Okay? This is an extracellular process. Meaning, an extracellular process. And respiration is an intracellular process. Meaning, it's a process inside the cell, man. Yes. Okay, so you understood this. So, first, son, look at the definition of respiration. Children have a lot of trouble with this. What is respiration? The process by which organisms break down glucose in their cells to release energy in the form of ATP, which is used for various processes. Meaning, a process in which, inside the cell, energy is produced with the help of the food we digested and with the help of oxygen, in the form of ATP, and that energy is utilized in all our life processes. The fact that I can speak today is because of ATP. Very good. Okay? Now, we are talking about respiration. First, you understood the definition of respiration, but now the question is, how many types of respiration are there, man? So, look, there are two types of respiration. Understand, I will explain this entire process to you. But for now, understand, there are two types of respiration. One is aerobic, and one is anaerobic. Aerobic means when we have oxygen, so the respiration happening in the presence of oxygen is aerobic. Aerobic. Okay? So, aerobic means "O" is coming, meaning there will be oxygen here. And anaerobic means here, there will be either less oxygen or no oxygen at all. Okay? In the absence of oxygen. Okay? Besides this, there are some differences, son. Like, these differences have been asked in exams. Very important question. In aerobic respiration, more energy is produced. Okay? More energy is produced. Whereas in anaerobic, less energy is produced. And you know what we are doing in respiration? We are breaking down glucose into energy. So, in aerobic, the glucose is completely broken down, man. Like it broke your heart. No problem. Okay. Okay. Okay. No, no, no, not that. Let's not talk about that. Okay? Trauma will come back, man. Don't talk about such things. Okay? Glucose is completely broken down here. But here, glucose is partially broken down. Not completely broken down. Okay? I'll give you examples with the help of a table. Come. An NCERT table, which has been asked repeatedly in exams, is this. Look, what is in this table? The entire chart of the breakdown of glucose. How is glucose broken down? Now, look, glucose first converts into pyruvate in a cytoplasm in your cell. Into what, son? Pyruvate. What is pyruvate? It's a molecule. A carbon molecule. Just understand that much. So, first, in the cytoplasm, glucose converted into pyruvate. Now, pyruvate has three paths. It's saying, "Brother, which path should I take?" This is one path where there is a lot of oxygen. So, if pyruvate goes first, in the presence of oxygen, then this respiration happens in the mitochondria of your cells. You already know. It happens in the mitochondria, and energy is released. Along with energy, two more things are released. Remember. One is carbon dioxide, and one is water. These two things are also being released. Is this clear? CO2 and water. Very good. Besides that, now two paths remain. In one path, where there is absolutely no oxygen. Absence of oxygen. When there is absolutely no oxygen, you know, energy is produced. Less energy is produced, but a product is formed, which is called what? Ethanol. Ethanol, that's what Sri Sri Honey Singh said, "Four bottles of wood work daily." Ethanol means that, yes, that's what it is. Ethanol. Okay? Okay? It's alcohol, ethanol. Okay? So, one is ethanol, and the other is carbon dioxide, and along with that, energy is produced. Besides that, if there is a lack of oxygen, meaning limited oxygen. Okay, this, you know, first, absence of oxygen, this happens in an organism called yeast. An organism called yeast. This process happens inside it. Okay? And if there is less oxygen? Like, sometimes we are playing football, and there is less oxygen in our muscles, then, you know what happens? Energy will be produced, but a compound is formed, which is called lactic acid. Those cramps you get suddenly, your leg starts hurting, your arm starts hurting. That is due to the formation of lactic acid. Yes, because your body is respiring in the lack of oxygen. Because of which, yes, this is the process. Understood? Because of which, what is happening? Yes. Lactic acid is being formed, and you are getting cramps. Very good, son. Now, look, I told you there are two types of anaerobic respiration. Aerobic, you must have understood. Anaerobic, I told you there are two types. One where there is absolutely no oxygen. One where there is limited oxygen. Now, these also have some names. The one where there is absolutely no oxygen, because alcohol is formed in it, so its name is alcohol fermentation. Alcohol fermentation. Okay? Its name is alcohol fermentation. Where does it happen? It happens in yeast. Yeast. Okay? Yeast does this. And what do our muscles do? Lactic fermentation. Because our muscles produce lactic acid. Energy is produced, but along with it, lactic acid is produced. And this question has been asked repeatedly: during intense workouts, I got cramps. Why did those cramps occur? Why did they occur? Because our body performed anaerobic respiration. Lactic acid was formed. Because of which, I am feeling cramps. This has been asked repeatedly. Okay? Now, I'll give you an example of this. Name the substance whose build-up in the muscles during vigorous physical exercise? See, it came. What is formed? Along with lactic acid, energy is being produced. Very correct. Next question. Which gas is released during anaerobic respiration in yeast? Which gas is released, son? Tell me. Which gas? Remember, man, carbon dioxide was formed, right, man? Yes, carbon dioxide. Very good. That's the spirit. Okay, next. What is this question? A boy is running a 400-meter race. Oh, it's the same question: what is happening? He is feeling pain. His heartbeat is increasing. Why is this happening? Tell me. Why is this happening? After intense workout, why does this happen? What should be the answer? Tell me quickly. It should be accumulation of lactic acid and increased CO2 concentration. When we work out a lot, one, our body has more carbon dioxide because we are breathing more, and two, lactic acid is formed, because of which my legs start hurting. Is this clear, son? Besides this, there is one more question. Complete the following pathway. Very important. A question like this comes. In this, you have to tell the first and second. What will be the first, son? Tell me. Glucose converts into what in the cytoplasm, son? Tell me. Pyruvate. Pyruvate. Very good. And pyruvate in the presence of oxygen gives what? Gives energy, gives H2O, and what else did it give? Yes, it gave CO2, man. Very good, correct answer you are giving. Okay, now let's talk about the human respiratory system. We are breathing now, son, let's see how I am able to breathe. So, without this, son, there are some steps. And this diagram is not asked that much. But still, let me show you once. First is the nose. Meaning, what is here? Nostril. Right? So, my first is this nostril. Nasal passage. With its help, what do I do? I breathe. Okay? From the nasal passage, I breathed. Took in oxygen. Now, what comes first? First comes, son, pharynx. First comes pharynx. Then comes larynx. Children get confused, thinking larynx comes first. Pharynx comes first. I'm giving you a trick. PL trick, meaning Profit Loss. Profit Loss. Remember it like this. So, first the P one will come, meaning pharynx, then larynx will come. Now, this pharynx, this is what we call the voice box. The fact that I can speak, my home, ding ding ding ding ding ding ding ding. Yes, what is this? Voice box. Okay? After the voice box, this thing you can see, this is trachea. What is it, son? Trachea. Now, there are some rings on the trachea, which I call rings of cartilage. Now, you know what these rings of cartilage do? They prevent the trachea from collapsing. If these rings weren't there, it would fall like this. It would fall like this. Okay? So, this is a very important thing. Okay, man? Now, air goes inside from the trachea, and here what happens? It divides into two things. Which we call bronchi. These are going into the two lungs, which we call bronchi. Okay? Now, the bronchi further divide like this. Into what? Bronchioles. Into what? Bronchioles. And at the end of every bronchiole, there is a bunch of grapes, like a bunch of grapes. Have you seen a bunch of grapes? A bunch of grapes. Like that, there is a bunch, which we call what? Alveolar sac. What do we call it? Alveolar sac. Meaning, it contains what? Alveoli. What is present? Alveoli. Right? What are alveoli? We'll talk about that now. Okay? So, did you understand this? Nostril, breathed in. Nasal passage, through which it goes inside. Then came pharynx. First pharynx. Second larynx. What is larynx? Voice box. Then comes trachea. What is in the trachea? Rings of cartilage. Which do what? Keep the airway open. Meaning, because of this, we can breathe. Okay? After that, what comes? Bronchi, left and right. Further ahead of one bronchus comes bronchioles. And at the end of bronchioles comes a whole bunch. And if I talk about one grape, meaning I am talking about one alveolus. Okay? Now, what is this alveolus, man? This is the most important. Now, this is the most important. What is it? Do you know? When you take oxygen in, and you exhale CO2. Do you know how you can exhale? With the help of alveoli, this is what is doing it. This is it, man, that is doing this job. Now you'll say, "Brother, how is it doing it? I don't understand." See, what alveoli do, alveoli use a very easy trick. Alveoli, first I'll tell you. It is a tiny balloon-like structure. Like, imagine this is alveolus. Now, alveoli, first of all, its property is that it is very thin. And a blood vessel is going through it. There is a blood vessel like this. What blood is it? It's the blood that has carbon dioxide. So, what does it do? It says to that blood, "Hey, give me your carbon dioxide, and keep my oxygen in the blood." Meaning, oxygen directly reaches our blood, and we exhale carbon dioxide. Who is doing this? Alveoli are doing it. Now, the question in your mind must be, "Okay, we agree. Alveoli are the site of gas exchange. We agree, man, exchange is happening here. But how is it happening? How is this possible? What magic is there?" So, for this, you have to read a love story. We will read a love story. Whose? It's a love story of hemoglobin and oxygen. See, what is hemoglobin? It's a respiratory pigment. Remember, what is hemoglobin? An iron-containing protein, meaning a pigment, which we also call a respiratory pigment. Okay? It is present in the RBCs, meaning red blood cells, of our blood. We will read about it in detail later when we start transportation. Now, it has a love. It has a love. It loves oxygen. So, remember, who is its main love? Its main love is oxygen. It loves oxygen a lot. So, now what happened? See, this was our alveolus. A blood vessel was going through here. Now, there is oxygen here. This blood saw oxygen. Oxygen. It said, "Hemoglobin, I want oxygen. Take my CO2." It's a love story. So, it gave CO2 back to the alveolus and kept oxygen with itself. Meaning, this gas exchange is possible because of hemoglobin. That's why we call hemoglobin a respiratory pigment. Remember, respiratory pigment. Very good. Okay? So, this is the entire process, son. Read this out: Oxygen from alveolar air diffuses into blood capillaries. Okay? Carbon dioxide from blood diffuses into alveoli. Meaning, CO2 has come into the alveoli. Now what happens? When we exhale, that CO2 goes out. This is the entire process. This alveolus. See this blood. What did the blood have? Gave CO2 here. Took oxygen inside. Because of whom did it take it? Because of hemoglobin. Okay, so the whole game here is hemoglobin's. Okay? So, we understood the properties of alveoli? Two properties. One, it is very thin, and it has blood vessels, with the help of which it can exchange. Very good, son. Now, look, in our lungs, besides this, at the bottom, there is this chest, rib cage, these bones, rib cage. And at the bottom, there is a muscle, which we call diaphragm. What do we call it? There is a muscle, which we call diaphragm. This muscle you can see, this is the diaphragm. Now, understand, the diaphragm is like this. Now, inhale. Take a breath in, son, quickly. Take a breath in. Meaning, the diaphragm is normally curved. But when we inhale, it becomes straight. It becomes flat. And when we exhale, it becomes curved again. And this is what needs to be remembered. When we inhale, what happens? First, the rib cage comes out. The rib cage, see, it comes out. Besides that, our diaphragm becomes flat. It becomes completely straight. I told you. Besides that, the chest cavity, meaning the size of the chest, increases. And when I exhale, what happens? In exhalation, the rib goes down. The diaphragm relaxes. The diaphragm is like this. If I inhale, it becomes straight. It becomes flat. Okay? MCQs come on this. And the chest cavity, meaning the size of the chest, decreases. Right? The size of the chest decreases during exhalation. Did you understand this, son? Tell me quickly. Have we understood all these concepts? So, let's look at some questions. With the help of which you will get clarity. Give the reason why rings of cartilage are present in the throat. What do rings of cartilage do? Prevent the windpipe from collapsing. Meaning, what is its job? It saves it from collapsing. Lungs always contain a residual volume of air. Meaning, lungs always have some volume. Even after you exhale, there is still a little bit inside. Meaning, air remains. Not all air comes out. Why doesn't it come out? Understand. To allow continuous exchange of gas and prevent lung collapse. If all the air goes out, the lungs will collapse. The lungs will collapse. Okay? Next, the diaphragm flattens and ribs are lifted up when we breathe in. Obviously. Why does this happen? So that the chest size can increase and more air can be taken in. Okay? Walls of alveoli contain an extensive network of blood vessels. Why? To exchange CO2 and oxygen. What needs to be done? To give oxygen to the alveoli, to take CO2. Okay? Very good. Is this clear? Let's look at the next one. Why is a respiratory pigment needed in multicellular organisms? Very important question. What is a respiratory pigment? Hemoglobin. Why is hemoglobin important in us? Because hemoglobin is involved in gas exchange. If there is no hemoglobin, then there will be no oxygen in your blood. So, hemoglobin is very important. Okay? So, in multicellular organisms, hemoglobin is very important, which is present in the blood. We will also read about this in detail later when we start transportation. Okay, next question. We will read about it now. Next, describe the exchange of gases in alveoli. How do alveoli do it, son? Exchange of gases. Remember, remember, remember, quickly. How do they do it? And why are alveoli richly supplied with blood vessels? Now, look, how do alveoli do it? Remember point by point. Each alveolus is surrounded by a network of thin-walled blood capillaries. Meaning, there are thin blood capillaries. Oxygen present in inhaled air diffuses from alveoli. Meaning, the oxygen we brought has come into our alveoli. And what does alveoli do? It sends that oxygen into the blood. And the CO2, carbon dioxide, that is in the blood, it calls it back to itself. Okay? Carbon dioxide from deoxygenated blood comes into the alveoli. Then what happens? During exhalation, that comes out of the alveoli. It comes into the lungs, and we exhale it. So, this is the entire process. Remember, it is very important. Right? This has been asked repeatedly: how do alveoli work? Okay, this is the end of respiration in animals. Right? And I remembered one line: that

There is a very beautiful line that says, "Take me far away." Take me far away, where you smile, that is my destination. Oh son, study, look behind, your mother is watching. Study, study. The exam is here. Next is about Respiration in Plants. Not poetry, but studies. What is Respiration in Plants? Do plants also respire? Absolutely, they do. How do they do it? Well, they do exchange, don't they? They don't respire, but they do breathe. They do exchange gases. How do they do it? Look, son, the first thing is with the help of stomata, I've already told you. Okay? Besides that, remember there are some pores. Plants have some pores which we call lenticels. Their stems, the stems of the plant, have some pores which we call lenticels. With their help, they exchange gases. Besides that, they also generally exchange gases with the help of the surface of the root. With the help of roots, they also exchange gases. Now, why are plants exchanging gases? Two reasons. One is to perform photosynthesis. Second, they also need to respire, man. They also need to produce energy, right? So they will also respire. Okay? Now, a very interesting question arises here: when it is daytime, plants perform both processes. See, they do photosynthesis, and they also do respiration. But as soon as night falls, to stay alive, they have to respire. Right? They have to produce energy. But at night, they can only and only respire. They cannot do photosynthesis because there is no sunlight. How will they do photosynthesis? So, sir, remember that plants give oxygen during the day. Why? Because a lot of oxygen is produced during photosynthesis. But at night, because they only respire. And what was produced during respiration, son? Remember. CO2 is produced, right? Energy, H2O, CO2? Yes. Because of this, plants release CO2 at night. Right? So, a question comes like this: Which of the following statements is true about respiration in plants? Which of these statements is true? So, if you read option D: Both photosynthesis and respiration occur in the leaf during the day. Both things happen. Okay? Besides this, how do fishes breathe? This also comes as a small question. The question comes that fishes, the breathing rate of fish, the breathing rate of a fish is higher compared to animals. Why is that? It's simple, man. There is less oxygen in the water, so it has to take in more water repeatedly so that it can extract oxygen from that water because it also needs to respire, right, dear? Respiration is necessary. Okay? Very good. So, first, remember that fishes use gills. They have a specialized organ. Just like we have lungs, they have gills to absorb dissolved oxygen from the water. Now, the question that comes in this, I am telling you. Why do aquatic organisms have a faster breathing rate? The simple answer is: because water has less dissolved oxygen. There is less oxygen, man. In water, compared to air, so you have to breathe repeatedly, man. So, remember they have a specialized organ which we call gills.

Now, respiration ends here. And let us start. The next topic, which is transportation. Now we will talk about the heart, from the heart. Let's talk about the heart from the heart. I'll just go and drink some water. Come on. Now you must be thinking, what is this transportation? See, transportation is also a life process. So far, we have studied two life processes. One was nutrition, and one was respiration. Let's summarize. What was nutrition? In which we had to eat food and obtain energy. How? We started from the mouth. What was in the mouth? Salivary amylase. Very good. Esophagus, through which food went to the stomach with peristaltic movement. Then came the stomach. What did the stomach have? Three brothers, all three destructive. HCl, mucus, and pepsin. Very good. Remember the functions of all three. Besides that, as the food was going down. It met two goons. Who was the first goon? One was the liver, and one was the pancreas. The liver did two things. The liver secreted bile juice and did two things. Do you remember? What did it do? Emulsification of fat and made the food alkaline, meaning basic. After that, this goon, the second goon, the pancreas, said that now I have to do three things. So it released three enzymes, if you remember: trypsin, lipase, and pancreatic amylase. Then the food went to the small intestine, where there were villi, finger-like structures. They absorbed the food. And the waste went to the large intestine, from the large intestine to the anus. This was human nutrition. And then we studied respiration. Remember the game in respiration. Where is the game? In your lungs. What is inside the lungs? Alveoli. What is in the alveoli? Blood vessels. And what is inside the blood? Hemoglobin, which is the respiratory pigment. What does it do? It calls oxygen to itself. With its help, your deoxygenated blood becomes oxygenated again. So, this has been the entire story so far. Now we are moving to transportation. Look at the next life process. There are three things in transportation too. There are three brothers here as well. Who are these brothers? If I talk about the first brother, it is blood. Blood is a tissue. Blood is a connective tissue. Okay? Who is the most important for transporting? Blood. Besides that, blood vessels, through which this blood is going to flow. And last comes the heart. Right? And the heart has said this to the heart. The heart has said this to the heart. You are getting cut again. Okay? So, what is the function of the heart? The function of the heart is to pump, nothing else. Oh brother, no, I gave my heart, I did this. No, the function of the heart is to pump. If you give your heart to someone, you are also finished. Completely finished. So, what is transportation? Transportation in living organisms refers to the process of moving food, water, oxygen, and other essential materials to different parts of the body. We have to take food and everything to different parts. Who will do this work? These three brothers will work here. The heart is a pumping organ, son. Don't give your heart to anyone. And if you have given your heart to someone, then see. You are considering them Ayushi. What if they turn out to be your friend Ayush next door? What if they are chatting with you by creating a fake ID? So, find out first. Okay? Yes. So, what is the function? Very good, of the heart. We will study about the heart in detail. It is important. First, let's start with blood. What is blood, son? See, blood is a type of connective tissue. You must have studied it in the ninth class. Oh ho, you didn't study in the ninth class. No problem. Okay? It is a type of connective tissue. Its color is red. Red color. Why? Because it has a respiratory pigment in it, whose story we have heard about. What is its name? Respiratory pigment called hemoglobin. Okay? Which is found inside red blood cells. So, see, before telling you the functions of blood, you will understand the functions of blood if you understand the parts of blood. Basically, how many parts does blood have? It has three parts. What is the first part? Blood plasma. Meaning, the liquid part inside the blood, because of which blood can move, what is it? Blood plasma. Its color, by the way, is a bit pale yellow. And what is inside it? Fluid medium carrying nutrients. Meaning, it has nutrients, waste, everything inside the plasma. Okay? Now, let's come to blood cells, or blood corpuscles. There are two types of blood corpuscles. You must know RBC. Not RCB, RBC. Okay? RCB fans, yes, WBC. Okay? So, one is red blood cell, and one is white blood cell. See, what does the red blood cell do? We have heard about it that it contains hemoglobin, and what does hemoglobin do? It is used in the transport of oxygen. It is used in the transport of both oxygen and carbon dioxide. Very good. The next is the white blood cell. This is a kind of warrior. What does it do? It protects our body. So, it provides immunity, produces antibodies against diseases. It is used to fight diseases. And there is one more thing, the third thing, which is platelets. Very important. You must have gotten injured sometime, and that wound heals in a few days. Why does it heal? Due to platelets. Meaning, what are these platelets? They help in blood clotting. Meaning, wherever there is an injury, the clotting that happens is caused by these platelets. So, these are all the functions of blood. Now, can't you write the functions of blood yourself? You can write the functions of blood yourself now. What is the first function of blood? See, the first function is what? To transport. Transport of what? Oxygen, nutrients, carbon dioxide. Very good. Second function, oxygenation. Because blood has RBC, and RBC has hemoglobin. Hemoglobin binds to oxygen. So, blood plays the most important role in the supply of oxygen. Okay? Blood is very important. Very good. Next, defense. Meaning, if any disease comes, who will fight it? WBC will fight it. So, it also provides immunity. Next is temperature regulation. Blood also regulates the temperature of our body. And clotting. I have also told you about clotting. Blood platelets cause blood clotting. Remember these five points, son. The function of blood is asked in the exam again and again. And children don't remember it. But you will remember it. Why? Because you have studied from PK Bhaiya, right? Come on, this is about blood. Now comes what? Blood vessels. There are three types of blood vessels. What are vessels? Tubes. There are three types of tubes. One is arteries, one is what? Veins, and one is capillaries. Let's understand them one by one. See, I'm telling you a trick to remember, son. Arteries, meaning 'A' is coming in it. And another word starts with 'A'. Away, away, away. Meaning, these arteries will always take blood away from the heart. Meaning, they will take blood away from the heart. Veins do the opposite. Veins take towards, meaning they take towards the heart. What are capillaries? They connect arteries and veins. Meaning, they are the middle path. They connect both. Okay? Very good. Okay? So, you must know this: carry blood away from the heart. Carry blood towards the heart. Okay, brother. Next thing to remember is that arteries always carry oxygenated blood. But there is an exception, like there is in class. A student who sits on the back bench, but when his result comes, everyone is shocked. Oh, how did he top? Right? Yes. You can also be that. So, similarly, here is an exception. Although it always carries oxygenated blood, there is an exception, which is the pulmonary artery. Pulmonary artery. Very good. Veins also always carry deoxygenated blood. Meaning, impure blood, meaning blood with CO2. But here too, there is an exception, the same one. Pulmonary vein. Okay? Very good. And capillaries carry both. Okay? Meaning, they carry both oxygenated and deoxygenated blood. Very good. Now, see, the pressure, son, the pressure in arteries is very high. Blood pressure. Why? Because arteries are taking blood away from the heart. And how does the heart beat? Dhak dhak dhak dhak dhak-dhak. Right? So, when they are taking blood like this, the blood comes with a lot of pressure. Here, the pressure is high. Here, it is low, and there too, it is low. Okay? Remember the thickness of the walls. The wall thickness of arteries is thick. It is thick. It is thin, and that is very thin. Now, why is it thick? Because it has to carry high-pressure blood. If it were thin, it would burst, man. If the pipe is thin, it can burst, right? Yes, very good. Next thing is valves. Remember, valves are only present in veins. Valves are present in veins. Now you will ask, brother, what do valves do? This question is asked repeatedly. See, son, this is your vein. Okay? Now, there are valves present like this in the vein. These, these, why are they there? Suppose blood is coming from your leg to your heart. Now, it is possible that that blood goes down, meaning the blood goes backward, and it doesn't reach your heart. This will lead to your death. So, to prevent that, valves are installed. As soon as the blood comes up, it gets locked here. Then it moves forward, it can get locked here. Meaning, that blood cannot go down. So, what do valves do? They prevent backflow. And this is the question that was asked. Valves in veins help in preventing backflow of blood. Very important, star mark it. It is asked again and again, what do valves do? Why are they present in veins? Because they prevent backflow. They prevent it from going backward. Very good, son. Okay? You understood the function? What are arteries doing? From the heart, to the entire body. And they are bringing blood back from the entire body to the heart. And capillaries are just connecting in between. Okay, brother? We have understood these things. Right? Now, there is some important information written here: the largest artery in our body is the aorta. These names are going to come up a lot, so remember them. Okay? Aorta. The largest artery is the aorta. Okay? The only artery that carries deoxygenated blood is the pulmonary artery. Similarly, the largest vein in your body is called the vena cava. What? Vena cava. And the only vein that carries oxygenated blood is what? Pulmonary vein. These are asked in MCQs, four things. So, you should remember them.

Now, let's move to the functioning of the heart. Let's talk about the heart from the heart. Come on. Now, a very important thing to understand comes here. How does the heart work? Right? How many chambers does the heart have? This diagram is very important. Right? Sometimes they ask it. Nowadays, it is asked less, but they can ask. I will explain it to you with a simple diagram. See, there is a heart. The heart has, brother, four chambers. Draw four chambers. Okay? See, on the left side, right side, you have to look like this, son, like this, left side, right side, left side, right side. Okay? This is left, this is right. Don't look like this, saying, brother, this is right, this is left. No, no, no. Look like this. This is left, this is right. Okay? So, there is a left side and a right side. Now, the upper part, it has two names. Either it is called atrium, or it is called auricle. Two names. And this is called what? This is called ventricle. What do we call this? We call this ventricle. This is auricle or atrium. This is ventricle. This is ventricle. This will be? Left, say. Left atrium, left ventricle. Right atrium, right ventricle. Now, see where the game is. Understand this whole thing, son. I will explain it with the help of a flowchart, a story. You will never forget it. It will take 5 to 10 minutes. See, this is your lung. Suppose this is the lung. What does the lung do, son? What does the lung do? It makes the blood oxygenated. Yes or no? Yes. So, oxygenated blood will come. It has to bring blood towards the heart. Okay, brother. Very good. So, blood comes towards the heart, first on the left side. Blood comes to the left side, from where? From the lung. This is the lung. Blood came from the lung, where? Towards the heart. Entry is on the left side. Okay? In the left atrium. Meaning, it is in the left atrium. Then it comes to the left ventricle. Meaning, the blood goes down like this. And after that, this blood leaves from here, leaves from here, and goes to the entire body. Meaning, the body will be here. So, now the blood that is going, son, is going to the entire body. It is going into your body. Okay? Now, what happened from the body? Respiration occurred, carbon dioxide was released. Now this blood has become deoxygenated again. Now this deoxygenated blood, you know where it will come? It will come back here, meaning to the right atrium. From the right atrium, it will go to the right ventricle. And from the right ventricle, it will now go back where? It will go to the lung. And this cycle will continue, continue. Now, the naming here is very important. I will show you the naming. First, you see the concept, right? Oxygenated blood comes to the left side, and deoxygenated blood comes to the right side. Came from lungs, to body, body to heart, and heart back to lungs. Very good. You understood this? Now, I will explain the entire story easily to you with the help of a very good diagram. See, who brings the blood? We have to remember these names. Obviously. Who brings blood to the heart from the heart? Veins will bring it. Which vein will bring it? Pulmonary vein. Now, from the left ventricle, who will take blood to the body? It will be an artery, which is the aorta. After that, blood will come back here, to the right atrium. Who will bring it? Vena cava will bring it. A type of vein. And after that, blood will go back to the lung, which the pulmonary artery will take. Now, this is not remembered by anyone, brother. I have a trick. Now he has a trick, brother. See, let's look at the trick, son. You have to remember a story. There was a badminton player, PV Sindhu. You must know her. So, see, PV Sindhu won a medal, and now she has to video call her family and show them that look, Mom and Dad, I won a medal. So, how will she do it? See, PV Sindhu said, "Ayyo, ayyo," like they say in South India, "Ayyo." So, what did she say? "Ayyo, get me a video call," meaning video call. And whom did she say this to? To her PA. They have PAs, right? Personal assistants, etc. Yes. So, she told them, "Yaar, PV Sindhu said, 'Ayyo, get me a video call.'" Whom did she tell? Her PA. If you remember this, your heart topic is finished. You know why? From lungs, where is the blood going? To the heart. Who is bringing it? PV. What is PV? Pulmonary vein. First of all. Okay? Now, from the left ventricle, blood is going to the body. Who is taking it? Aorta. Who? Aorta. Aorta is what? Ayyo. Ayyo means Aorta. Then she said, "Video call." Now, see, who is bringing blood back from the body to the right atrium? It is Vena cava. Vena cava, Vena cava. Meaning, VC. Very good. And that blood is going back to the lung, which the pulmonary artery will take. So, meaning, from the story, your entire heart can be finished now. Did PV Sindhu say, "Ayyo, get me a video call"? Whom did she tell? Her PA. Just through the story, all the naming should be remembered by you. Now, do you understand? Very good. If you understood this, tell me once. Now, there are some pointers here, son, which you will have to remember. The first pointer, this middle wall, we call it septum. What is this? This is the septum. Dividing wall. What do we call this, son? We call it septum. If you can see it clearly. Okay? Besides that, I have told you the entire flow. Remember one thing. Vena cava, see, Vena cava has two entry points. One is from the lower body. Vena cava comes from here, and one from the upper body. Meaning, one from the upper body, one from the lower body. Blood comes from both to where? Vena cava brings it, and it goes into the right atrium. Is this clear? Very good. Besides that, there are some differences, son, which you should remember. What are those differences? First, the difference between atrium and ventricle. Okay? Atrium and ventricle. By the way, what is the size of your heart? Do you know? It is the size of your fist. It is just this much. Yes. Your heart is this small. But it does such important work, right? That's why don't give your heart to anyone. Okay? The heart is very important. Don't give your heart to anyone. Yes, okay. Understand the difference between atrium and ventricle. This is the upper chamber. This is the lower chamber. By the way, the walls of the atrium, son, are thin. Whereas the walls of the ventricle are thick. Why? You can see it too. See, the walls of the atrium are so thin. But the ventricle's walls are so thick. Why? Because the ventricle has to pump blood. It has to pump blood at high pressure. So, its walls should be thick, otherwise, it will be the same situation. The heart will burst, what else? Okay? What do they do, son? Atria receive blood, and ventricles always do what? They pump blood. They pump blood. Okay? This is very important. Where does oxygenated and deoxygenated blood come? This is very important. I hope you have understood this entire diagram. Did you understand or not? Many questions come from this, son. Remember. Left, oxygenated. What did I say? Left atrium, left ventricle, body. From the body, back to the right atrium, right ventricle, lungs. At the lungs, your blood is converted from deoxygenated back to oxygenated. Okay? Now, if you can see, there are four chambers here. So, the question comes, why do we have four chambers? I will tell you the answer. See, it is written here too. Why are there four chambers? To prevent mixing of oxygenated and deoxygenated blood. More oxygen will be supplied to the body organs in a better way. See, we are a type of multicellular organism. We need a lot of energy, man. So, if our oxygenated and deoxygenated blood mixes, you know what will happen? The oxygen supply will not be as good inside the body. That's why there are four chambers. Why? So that, see, oxygenated will be here, and deoxygenated will be here. So, it is divided. Oxygenated and deoxygenated are divided. This increases our efficiency. Okay, brother, very good. Besides that, if you have seen, there are two cycles here. There are two cycles, son. One cycle is what? See, son, pay attention here. One cycle is. See, a double cycle is running here. We have double circulation. How? One cycle is from lung to heart and back from heart to lung. You can see, from lung to heart and from heart to lung. One cycle. What is the second cycle, son? From heart to body and from body to heart. Meaning, there are two cycles here, brother. Yes. That's why we say humans have double circulation. So, this first, this cycle you can see, from lung to heart, heart to lung, we call it the pulmonary circuit. Pulmonary circuit. And this, which you can see, we call it the systemic circuit. It is written here too, I will explain it to you in detail. First, what is it? Pulmonary circuit. So, see, what is the pulmonary circuit? Blood flows from heart to lung and back. Okay? That's the first one. Besides that, there is systemic circulation, or we can call it the systemic circuit. What is it? Blood flows from heart part to the rest of the body and returns. So, this is what? This is the second circulation. Now, why are these two circulations important? You will see questions in your exam again and again, son. I am telling you today, a question will come in the exam. Why is double circulation present? What is the answer? Let's see. What happens with double circulation? It keeps the oxygen-rich blood separated from the oxygen-poor blood. It ensures efficient supply of oxygen to the body. It maintains high pressure in the systemic circulation for proper distribution. So, what is happening with this? One, oxygen supply is increasing. Second, all parts of our body are getting blood, getting oxygen. Meaning, respiration is happening. Respiration happens because of oxygen. Yes. So, because of this, double circulation is very important for us, son. Okay? Did you understand this? Here, I have also written three points that why it is necessary to have four chambers. I have written them here for you: first, to prevent mixing of blood. To ensure efficiency of oxygen supply. Second point, son, remember these. Third, essential for warm-blooded animals. I will explain this. Now, see, some animals are cold-blooded, and some are warm-blooded. What is the difference? We can change our body temperature. Our blood can control our body temperature. Right? What do we call this? We call this warm-blooded animals. Which we are. There are many other organisms too. Whereas some organisms are cold-blooded. Whose blood cannot control their temperature is called cold-blooded. So, all warm-blooded animals, for them, it is very important to have four chambers and double circulation. If this is not there, they cannot survive. Okay? So, a four-chambered heart is necessary. This is what a real heart looks like, son. See, today I have shown you its heart too. Right? No child should write in the answer that brother, why are there four chambers? The four chambers for boys, you know why? One has Riya, one has Ayushi, one has Sunaina, one has Neha. No, son, don't write this. Understand the logic of four chambers. Okay? Which component of blood helps in clotting? Platelets do. Very good. Next, which of the following statements is/are true about the human heart? Which of these is true, son? Very good question. Asked again and again. Tell me, the first statement: the right atrium receives oxygenated blood. The left one receives oxygenated. The right one receives deoxygenated. Right? You know how you can remember this? There is a book called RD Sharma. So, you should remember RD, meaning right will always have deoxygenated. So, this is wrong. Let's move on. The left atrium transfers oxygenated blood to the left ventricle. Very good. This is absolutely correct. The left atrium transfers to the left ventricle, and from there, it goes to the entire body. Who takes it? Aorta. Okay? Let's look at the next one. The right atrium receives deoxygenated blood through the vena cava from the upper and lower parts. Is this statement true? The right atrium, see. Remember the diagram of the right atrium. Does the right atrium receive deoxygenated blood? Yes, it does. Where does it receive it from? Vena cava. Whenever you are confused, remember. PV Sindhu, what? PV Sindhu, what did she do? Ayyo, get me a video call. Whom did she tell? Her PA. Okay? So, this statement is also absolutely correct. Let's look at the last one. The left atrium transfers oxygenated blood to the aorta. Oh no, brother, the left atrium, how will it transfer to the aorta? The left ventricle transfers it. So, this is wrong. So, the option should be B and C, meaning option C. Very good. See, this was a very good question. Next, assertion-reasoning questions are being asked a lot nowadays. See, the wall, the wall of atria. Atria, meaning, brother, it is the same as atrium. Okay? The wall of atria is thicker than those of ventricles. No, no. The walls of the atrium are thin. The walls of the ventricle are thick. Because the ventricle has to push. So, in this, statement A itself is wrong. So, its correct option will be D. Right? If you have done assertion-reasoning, you will know why the answer is D. If not, practice it. It is being asked in exams nowadays. Next question, label the parts A and B in the diagram of the human heart. See, brother, you have to look at this. This is left. This is left. This is right. Look like this, son, yourself. Right? Is this left or right? This is the upper part of the left. So, what is this? Left atrium, or you can also call it left auricle. And what is this? Right. Right, say, ventricle. Very good. Right ventricle. Very good. Okay? Next, differentiate between pulmonary artery and pulmonary vein based on the type of blood they carry and the direction of blood flow. It's just a differentiation question. Between what? Pulmonary artery and pulmonary vein. See, where did the pulmonary artery come? That artery which goes from the heart to the lung. See, PA comes at the end. PA comes at the end. Meaning, the blood that goes from the heart to the lung is the work of PA. And what does PV do? Pulmonary vein brings it into the heart. Yes. So, meaning, what does the pulmonary artery do? Deoxygenated blood. And what does the pulmonary vein do? It carries oxygenated blood. It takes blood from the heart to the lung, and it takes blood from the lung to the heart. Did you understand? Did you enjoy it? Is it going into your brain, or is it like this? Brother, what are you teaching? Teach something that is understandable. Why is nothing understandable? Okay? It will come, it will come. This is something that requires a little practice. Because when you study for the first time, you don't remember the names. Practice the names a little. Next, why are the walls of the ventricles thicker than the walls of the atria? I told you just now. The walls of the ventricles are thicker than the walls of the atria? Because ventricles have to pump blood with greater force. Because of this, I told you, it has to pump. Okay? Why do arteries have thick and elastic walls? Why are the walls of arteries thick? Because arteries have to pump? Who is taking the pumped blood away from the heart? Away? Arteries. So, meaning, it is high-pressure blood. Because of this, their walls are thick. It is written here too, due to high pressure. High pressure is the main reason.

Come on, now see, there is one more topic. Just like I told you, we have four chambers in our body. But not everyone has four chambers. For example, if I talk about fishes, then look carefully. We also call fishes passage. Now, these fishes have a two-chambered heart. Yes. So, what do they have? They have only and only single circulation. And these are called cold-blooded. Right? Cold-blooded. Besides that, besides that, amphibians. You must know amphibians, like your "tar tar." Yes, a photo is also made. Look. It looks like your friend's face. This one too. See, see, it looks like a friend's face. Yes. So, it has three chambers. So, it cannot do double circulation. It is doing incomplete double circulation, and it is also cold-blooded. Okay, brother? It cannot regulate temperature. Reptiles also have three chambers, like crocodiles, and they are also cold-blooded, and they also cannot do complete double circulation. But birds, meaning aves, and mammals, which we are. Birds, meaning aves, and mammals are two types of species that have four chambers. They perform complete double circulation. And they are warm-blooded. Meaning, they can control their temperature. Okay? So, a question was asked here: Why do more chambers in the heart matter in evolution? This is a slightly high-level question. Evolution, meaning as we have evolved. So, why were four chambers put inside our body? So, in this, you didn't have to think anything. You had to write the same answer. Meaning, why is four chambers present? Why? Say, to ensure the supply of oxygen. Oxygen will keep supplying to the body. It will supply well to all parts. Right? So, that's what you had to write in this. Besides that, it is necessary in warm-blooded animals. Right? If they want to maintain their temperature, that's it. And besides that, to keep oxygenated and deoxygenated blood separate. Yes, very good. That's the point. Okay? By the way, the name of that middle wall is septum. The middle wall of the heart, the septum, it is septum. So, therefore.

The blood here cannot go there. The children must be thinking, why isn't the blood from here going there? Well, there's a wall in between, which we call the septum. Okay? Very good. Now let's move on to the next system, which is the lymphatic system. I'll drink some water. Now, what is this lymphatic system? Tell us, brother. See, the lymphatic system is a slightly different type of system, which is a bit complicated to understand. But why worry when PK Bhaiya is here. See what happens, right? First, understand what lymph is. Lymph. Lymph is called as tissue fluid. Meaning, it's a fluid of the tissue. Now, understand what's happening in the story. Remember capillaries? Yes. Which connect both. So, these capillaries are carrying blood and other things here and there. But what happens here is that some substances leak out. Right? They leak out. For example, some substances have leaked out. See. Formed when plasma protein and some blood cells escape. Escape, meaning leak through the pores of capillary walls. Meaning, some substances have leaked through the walls of the capillaries. Suppose there was a tissue in my body somewhere. A capillary was going through it. This substance leaked from it. Right? So, many such substances, what happens? They accidentally leak out. Into the intracellular space. Meaning, these substances leak out into the spaces between the cells. Okay? So, the substance that forms there, the fluid that forms, that fluid is what we call lymph. So, how is lymph generated, child? Lymph is generated due to leakage. So, lymph is nothing. When things leak out of capillaries, then lymph is formed. So, lymph is a colorless fluid. Remember, it has no color, and it contains very little protein. So, when blood is flowing, things leak out due to the capillaries. Now, what all things leaked out? RBCs never leak out. RBCs are essential. Right? Because they have hemoglobin, they don't leak out. But WBCs, sometimes, what happens? They leak out. Okay? So, here what happened is that in our tissues, this leaked out. And a fluid was formed, which is called lymph. Now, this lymph also contains WBCs and many proteins. So, it has to be brought back into the blood. So, who will bring it back into the blood? The lymphatic system will bring it back. So, the lymphatic system pulls all of this and brings it back into the blood, saying "come, come, come, come," and throws it back into the blood. This is the lymphatic system, and nothing else. See, this lymphatic system, these green colored things you see, this is the entire lymphatic system. Wherever lymph is produced, what happens? They have a tube called lymph vessels. What do lymph vessels do? They pull it and bring it, and then put it back into the blood. Okay? So, you can read here as well. Lymph flows into lymphatic capillaries. It has capillaries. So, this collected lymph, the colorless fluid. Remember, colorless, it comes into the capillaries. Which join to form larger lymph vessels. Then it reaches the lymph vessels. These vessels finally open into larger veins. Meaning, they go into the veins. Reconnecting to the blood stream. It has come back into the blood. Okay, brother. What leaked out has come back. Now it's okay. Now it's okay. Meaning, this lymphatic system is solely for saving the leakage. Okay? Now, what are its functions? Functions are asked many times, child. What are the functions of lymph? See, the first function is clear. What? Transport of digested and absorbed fat from the intestine to the blood. Meaning, all this digested food and whatever has leaked out, it has to be brought back into the blood. The first job is obvious, it's clear. Second job, see, drain excess fluid from tissues. Meaning, what happens is, sometimes too much water or some fluid accumulates in the tissues. So, the excess fluid that has accumulated comes with the lymph, and it also comes into the blood. So that the tissues are not harmed. Not damaged. Okay? So, the excess fluid also comes back into the blood. Lymph contains lymphocytes. Lymphocytes are nothing. What are WBCs? White blood cells. And what do white blood cells do, child? They provide protection. So, lymph has another function, what? Defend the body against infection. Meaning, lymph has three functions. One, it prevents infection. It holds us back, protects us. Second, it brings everything back into the blood. Third, whatever remains in excess, the excess of fluid in tissues, it also puts it back into the blood. Right? It's quite dangerous, this lymph, it's very important in life. Okay? If you just remember these three functions, that will be enough for you, child. Let's look at its question. What is asked? Which of the following is not a function of the lymphatic system? What is not a function? "Not" is written, child. Transport of digested fat from the intestine. This is there. This is a function. Return of excess tissue fluid. This is also a function, brother. Oxygen transport. It has nothing to do with oxygen. Oxygen doesn't come without hemoglobin. Hemoglobin is essential for oxygen. So, this is option C. Okay? This is not a function.

Now let's talk about transportation in plants. How does transportation happen in plants, child? Understand. Plants also transport. How do they do it? There are two ways. And you studied this in the ninth grade. But I know you didn't study it in the ninth grade. I know, man. I can understand. No problem. So, there are two types. One is xylem. One is phloem. You studied this. They were tissues. What does xylem do? It transports water and minerals. Phloem transports food. This difference between xylem and phloem is asked repeatedly. Look. See, what does xylem do? Conducts water and minerals from the root to the leaf. Meaning, it brings it from the root to the leaf. What does phloem do? Conducts food from the leaf to all parts. Meaning, where is food made? It's made in the leaves. Photosynthesis, and it reaches the entire body. Okay? Second. Also, xylem is mainly made of dead elements. You must have studied which cells are in xylem. So, there are some cells. If you can remember, it's not asked much. Tracheids, vessels, xylem parenchyma, and xylem fibers. Only xylem parenchyma is alive within it. The other three are dead. That's why we say xylem is composed of mainly dead elements. Whereas, phloem is the opposite. Phloem is mostly made of living things. For example, it also has four parts. Phloem fibers, sieve tubes, companion cells, and phloem parenchyma. Only one is dead here. Which one? These phloem fibers. They remain dead. The rest are all made of living things. Now, a big difference is coming. See, xylem transport is unidirectional. Meaning, see, how xylem transports is from the root upwards. Now it cannot move left, right, up, or down. It can only move in one direction. But this phloem is bidirectional. Because food is made in the leaves. Now, from the leaves, food will go upwards and downwards. It will go in both directions. So, transport in phloem is bidirectional. Remember, this is also asked repeatedly. This difference is very important. This table of differences is also asked repeatedly. Now the question arises, how does transport happen? Understand. Let's talk about xylem. In xylem, there are two ways of transport. One is root pressure. See, there are the roots of the plant. What is outside the root? Tell me. What is outside the root, child? There is water outside the root, obviously. There is less water in the root, and more water outside. Did you study this? Osmosis, from high pressure to low pressure. So, where there is more water, what will happen? Water will come inside. Obviously. So, one is a very easy process, which we call root pressure. The root absorbs water, and it pulls the water due to osmosis, water moves from high pressure to low pressure. The second process is very important, and you have studied it. You studied it a little while ago. Yes, transpiration. Remember transpiration? What used to happen in transpiration? Water used to evaporate from the leaves in the form of water vapor. Remember? Now, what happens? Now, what has happened in the leaves? Tell me. Water has evaporated from the leaves. Meaning, what has happened at the leaf now? There is low pressure at the leaf. And what is below? What is in the root? There is high pressure. So, why will water come from below to above? Because it will move from high pressure to low pressure. Meaning, transpiration is also essential for transporting water. If there is no transpiration, water will not rise upwards. Understand this point? Yes. Okay? So, I told you two ways. One, what did I tell you? See, child, xylem tissue transports water and minerals from the root to the leaves. Water enters the root by osmosis. See, I told you by osmosis, and moves upward through xylem vessels. Okay? It moves upward through xylem vessels. This upward movement is called ascent of sap. Meaning, this movement of water from the root upwards is called ascent of sap. Sometimes it is asked, what is ascent of sap? The movement of water from the root in an upward direction by xylem is called ascent of sap. Now, there are two reasons. One is root pressure. I told you the root pulls it. And the other is transpiration pull. Transpiration pull, which I am telling you. You know what transpiration is? The loss of water in the form of water vapor by stomata. Right? So, transpiration pull is happening there. Why? Because what is happening there? Low pressure. Below is high pressure. That's why it moves upwards. Okay? So, remember, its one function is pulling water upwards. And one function you have already studied. It removes excess water. Right? Transpiration removes excess water. But it also helps in bringing water upwards. Transpiration plays a very important role in pulling water upwards. Okay, brother? Understood? Very good.

Now let's talk about phloem. How does phloem do it, child? So, see, phloem carries food from the leaves in both directions with the help of, meaning, phloem carries food from the leaves in both directions. Okay? And that process is called what? Translocation. What is it called, child? Translocation. If anyone ever asks, what is translocation? It's nothing. The movement of food from the leaf to other parts of the plant with the help of phloem is called translocation. Okay? So, the movement of food is called translocation. Okay? Phloem transports prepared food from leaves to the other parts of the plant. This process is called translocation. Okay? It requires energy because it has to go in every direction. So, it requires energy. Understood? That's all in plants. There is xylem, there is phloem. Xylem is for minerals. And what is it doing? Yes, it's doing food. Very good.

Now let's look at the questions. Which of the following statement correctly explains the transpiration pull of the plant? Which of these statements is about transpiration pull? So, if you look, what is it? Read option B once. It is caused by evaporation of water from the leaf surface, pulling water up through the xylem. This is exactly what happens. Water evaporates from above due to evaporation. Low pressure is created here. Yes, very correct. Wow, brother. Okay. Understood this. Next. The process in which transport of soluble products of photosynthesis takes place is known. Tell me. Tell me. How is digested food transported? What is it called? You just studied it. Translocation. That's it. You've become smart.

Okay, this is a very nice question. Think about it and tell me. If you look carefully at this question, you need to focus on the diagram. What type of process is this diagram showing? If you look carefully at this diagram, see what has happened. There was a leaf above. Water vapor went from the leaf, and then see, water started going upwards from the root. Water is moving upwards with the help of transpiration. This process is what we were calling transpiration pull. Meaning, the pull that is created due to transpiration. Okay? So, what can we call this process? We can call this process transpiration. A pull has been created due to transpiration. Very good.

Now we are moving to the last topic of this chapter, which is excretion, child. Excretion is very important. Okay? Questions are also asked from this. And see, I have observed that there are two types of students. One is students who are very confused. And the other are students who know what they don't want to do in life. For example, they know they don't want to study. But you have to study, child, exams are coming, so become the first type of student, even if you are confused, but you have to study, man. Right? There were some students in our school too who were clear that brother, we will not study at all.

So, what is excretion, child? See, what we studied before was egestion, removing undigested food. What is excretion? See, excretion is the biological process of removing harmful metabolic waste like urea and uric acid from the body. Meaning, we will remove all harmful substances, urea, nitrogen compounds, etc. Okay? From our body. Now, how does it happen, child? This diagram is also asked to be drawn repeatedly. You should memorize it. It's very simple. Where are the kidneys located, child? Kidneys are located here. People think they are located here. No, they are located here. They are at the back. Okay? So, these are two bean-like structures, which are our kidneys. There are two kidneys in our body. So, what happens is that blood comes here. Right? Blood came here. Okay? Now, who brings the blood? So, remember, renal artery. There are two renal arteries, left and right. So, the one that goes to the left kidney will be called the left renal artery, and the one that goes to this right one will be called the right renal artery. Okay, brother? Blood came through the artery. Now, there is dirt in this blood. Now, the dirt will be cleaned inside the kidney. All the germs, germs, I'm saying nitrogen compounds, etc., will be filtered. How it happens, we will talk about that now. Okay? Then what will happen? The blood that has been cleaned. That blood will go back up with the help of the renal vein. Meaning, there are two renal veins, one will be the left renal vein, and one will be the right renal vein. Okay? Now, the waste that remains, excess water, nitrogen compounds, all that, you see these two pipes. These pipes are ureters. What are they called? Ureters. Okay? There is a left ureter. There is a right ureter. Okay? With the help of the ureter, it comes here. And this is your urinary bladder. You store your urine in the urinary bladder. And with the help of the urethra, you expel it out. Okay? So, the flow is: kidney. Blood came to the kidney. It cleaned the dirt. Dirt, ureter, urinary bladder, urethra. Below, what did you do? Whatever you call urine, it contains nitrogen compounds, excess water, many things. Okay? So, remember how it happens. What does the kidney do? Filters nitrogenous waste. First job. What does the ureter do? Carries urine from the kidney to the bladder. The bladder stores. Stores urine. And releases urine out. Who? Urethra. With the help of the urethra, you expel urine out. Now, a question is running in everyone's mind, brother, we will memorize this diagram. It's not a very difficult diagram. Everything is clear in this diagram. Okay, remember one more thing here. This big one you see, this is the aorta. What is this? Aorta. Do you remember what comes from the heart? What comes from the heart? Aorta comes from the heart. So, this aorta divides into renal arteries. These two small ones going are renal arteries. The big one is aorta. And the one that is taking it back, do you know who it is? Tell me, who is it? It's the vena cava. Yes. So, aorta brought it. Divided into renal arteries. Cleaning happened here. The pure blood, where did it go back? Where will vena cava take it? To the heart. Where will it take it to the heart? Right. Right. Right. Very correct.

Okay, understood this. Now let's talk about what is special in the kidney, brother? What is happening in the kidney? So, in the kidney, there is a nephron. What is a nephron? A nephron is a structural and functional unit of the kidney. Meaning, the most important thing in the kidney, you know, there are millions of nephrons in one kidney. And these nephrons, in a way, perform the function of filtration. Responsible for filtration of blood. How do they do it? There is a story. A story of three steps. This diagram, brother, you try to memorize it. It's asked very rarely. But see, you can try. If you can draw it, draw it. Okay? What am I saying? Don't draw all these things. Just focus on this yellow portion. This yellow portion you can see, just focus on this portion, like this. Right? This entire yellow portion. Just focus on this. Okay? Now I will explain how. See, blood came. There are three stories, in three parts. Meaning, there are three steps. I am going to tell you how the nephron filters blood. There are millions of nephrons in one kidney. How does one nephron work? I am going to tell you. Okay? First, blood will come. Blood came in, came in, came in, came in. Imagine it like this, blood said, "Won't you welcome us?" So, the nephron said, "Will we? Will we? Absolutely, we will." So, it gave it a capsule to eat. It gave a capsule. Imagine. It gave it a capsule to eat. And as soon as it ate that capsule, it started to glow. It started to glow. It started to glow. It said, "Okay. Now this is our first step." As soon as blood came in, this thing you can see, we call it Bowman's capsule. What do we call it? Bowman's capsule. And inside this Bowman's capsule is the glomerulus. And what does this glomerulus do? It glows, glows, meaning it started shining. That's why I said, "Glo, glomerulus." And this glomerulus does filtration. Meaning, the first filtration happens here. It pulls all these things. It pulls all the dirty things from the blood into itself. And it puts them here. Okay? Now, the blood says, "Oh, thank you, glomerulus, man. Okay, I'm leaving, my work is done." So, now see, the blood starts to leave. It's going, going. Then the blood realizes. It realizes. "A scam happened to me." So, a scam happened. So, how did the scam happen? You know, that glomerulus, I said, "Yes, yes." What did it do? I said, "Tell me, tell me." It took all my good things, like my water, my proteins. That's wrong, right? I said, "It's wrong." So, I said, "What will you do now?" So, the blood said, "I will go back and get my things back." Now, see, the glomerulus is a good person. So, when it went back, see here, this thing you can see winding around, what is happening here? Reabsorption is happening here. And this process is what we call selective reabsorption. Meaning, the good things of the blood, the things the blood needs, the blood takes them back. Okay? Now the blood says, "Thank you, man. Okay, this entire loop is traveled, and the blood leaves from here." Now, what is the third step? Now, all the dirt gets stored here. Okay? And this is what we call the collecting duct. This part is the collecting duct. And this process is what we call tubular secretion. Meaning, all this dirt, we finally put this dirt into a tubule, meaning into a tube. And this is what we call tubular secretion. So, see, child, there are three parts. With the help of the story, you will remember the whole thing. What is the first part? Glomerular filtration. What happens? Blood enters the kidney, and in the nephron, nitrogenous waste, glucose, water, amino acids, and excess salts are filtered out. This initial filtrate enters the Bowman's capsule of each nephron. Okay? What happened in the story? First, it came to Bowman's capsule, "Won't you welcome us?" Here, have a capsule. It started to glow, shine. Meaning, glomerular filtration happened. Remember the first step. Child, shall I tell you a trick? Just remember these headings. You can create the content inside. You have that skill within you, I know you can create the content inside. Remember glomerular filtration. The next step is selective reabsorption. I told you, when he was betrayed, what did he say? He asked for his things back. Right? As the filtrate moves through the nephron, useful substances such as glucose, amino acids, salts, and a significant amount of water are reabsorbed. Meaning, he asks for them back. Okay? Now the blood has left. Now what is left? Now, finally, tubular secretion happens. Meaning, urea, additional water, and excess salts are secreted into the tubule. Meaning, all the dirt, urea, etc., excess water, all of it reaches the tubule, the collecting duct I told you about, the collecting duct. Okay? Which then opens into the collecting duct. The urine then flows from the collecting duct into the ureter. Meaning, now see, from the collecting duct, where does it go? From the kidney, where did the blood go? Ureter. Urinary bladder. Urethra. Yes. So, three destructions, three brothers, three destructions. How will you remember? GST. GST is being applied to everything these days. GST: Glomerular filtration, Selective reabsorption, and the final is Tubular secretion. What a thing, friends.

Let's do some questions, right? So, I have explained this entire process to you here. You can see how urine is formed, child. How is urine formed? I have explained the entire process to you. Then, who transports urine? Ureter does. Who stores it, child? Urinary bladder does. And finally, from where does excretion happen? Excretion happens from, tell me, with the help of the urethra. When we feel, "No, no, now I have to go, brother." Right? Yes. Then, with the help of the urethra, we expel urine out.

Now, tell me some questions. Which part of the nephron is responsible for filtration? Which part is it? Which part of the nephron does filtration, child? It was given a capsule. It was glowing inside. Glomerular filtration, meaning Bowman's capsule. Very good. Next question. How is urine produced in the human body? Now, whenever this question comes, it's asked repeatedly, how is urine formed? So, you have to explain the entire nephron process here. You have to explain that blood came to the kidney. There was a nephron in the kidney. Now, three steps happened in the nephron. GST: Glomerular filtration, Selective reabsorption, and Tubular secretion. So, you have to explain this entire process here. Okay? Explain the basic process of urine formation. Then you will explain the entire process. Meaning, you have to explain all three steps. Okay? State the function of each of the following human excretory system. First is kidney. What does the kidney do? The kidney performs filtration. The kidney has nephrons. So, who is filtering the blood? It's the kidney. What do ureters do? Transfer urine from the kidney to the urinary bladder. What does the urinary bladder do? Stores. Stores urine until until we urinate. Until then, it stores urine. It's not like it will store it for a lifetime. No, it has to be expelled, brother. Yes, okay. Write one specific function each of the following organs in relation to excretion in human beings. Okay? Renal artery. Tell me, what does the renal artery do? The artery brought it from the heart. Towards whom? Towards the kidney. It brings the blood, which has impurities, to the kidney. Meaning, the renal artery carries the toxic blood. It brings the blood containing toxic substances to the kidney. Urethra. You urinate. Glomerulus. What is happening inside it? Filtration is happening. Tubular part of the nephron. What is it doing? It's doing tubular secretion. Right? Tubular secretion. All the urine that is formed goes from here to the collecting duct, and from the collecting duct, further to the ureter. Did you understand? You can also see. The tubular part of the nephron reabsorbs useful substances like glucose, amino acids, and water. It secretes additional waste into the filtrate. Meaning, its main job, child, is to understand that this tubular part, the dirt from the blood came. It adds more things to that dirt. Like extra water, glucose, etc. Okay? So, it has another function, what? That it adds. Remember, it is also written here that all the extra things, substances like glucose, amino acids, it secretes additional waste into the filtrate. Meaning, it adds more waste to all that dirt. Okay? Very good.

Did we understand this entire story, child? Where will these notes be found? Students are asking. You will find the notes, man. In the description on Telegram, why are you taking so much load?

Okay. What is hemodialysis, child? There is a small column in NCERT about hemodialysis. Hemodialysis means artificial kidney. Okay? For those whose kidneys fail, a whole process is involved. Just understand the definition. Hemodialysis is a medical treatment used to filter and clean the blood of people with kidney failure. For those who have kidney failure, this process is used to clean their blood, which is called hemodialysis. Dialysis means cleaning blood. Okay? Okay? So, with the help of a machine, blood is drawn out, cleaned, and the blood is put back.

Okay, child, let's look at a question. What will happen if kidneys stop working? How is this condition treated in a hospital? If kidneys stop working, you know what will happen? Blood will not be cleaned. If blood is not cleaned, toxic substances will form, and ultimately, death will occur. Now, how is this solved in a hospital? One is dialysis. Hemodialysis, which I told you about. And the second process is kidney transplant. These are two processes. One is dialysis, and the other is kidney transplant. With the help of these, this can be solved.

Okay, one last topic remains, which is excretion in plants. Then this chapter will end. I know you are tired. I am not tired. You got tired? I will hit you. Yes. Don't get tired.

Okay, excretion in plants. See, do plants also excrete? Yes, they do, brother. How do they do it? First, they release carbon dioxide. They release oxygen. Right? Obviously. So, first, oxygen and carbon dioxide are diffused through stomata. That is also a type of excretion for them. That is also an excretion. Okay? Next, excess water is removed by transpiration. That is also excretion for them. Whatever excess water they have, they leave it out on the leaves. Okay, brother? Understood? Next. Plants can even lose some of their old parts like old leaves and bark of the tree. Meaning, what happens? They start shedding their old leaves. A very good concept, understand. Plants store their waste in the leaves. Inside the leaves, you know? You see those leaves that fall, you know why they fall? Because the plant's waste was stored in them. Yes. So, plants store waste. In the leaves, inside the leaves. Then they shed them. Shed them. Okay? Other waste products like resins and gums, especially in old xylem cells, which can also be lost by a plant. Understand, you have seen some plants from whose trunk, some gum-like substance comes out. Have you seen glue-like substance coming out, rubber coming out? Do you know what that is? That is all the plant's waste. Yes. So, plants also remove their waste in this way. How? Like resins and gums. And last, plants also secrete some waste into the soil. Meaning, they also release their waste particles into the soil with the help of their roots. So, if it is ever asked how plants excrete, do plants excrete? Yes, they do. By exchanging gases, by releasing water, with the help of gums and resins, they store it in the leaves and shed those leaves. And the roots, with the help of roots, they also excrete into the soil. Okay? Very good. So, this was the entire process. You can see this. You have seen this, a big tree. Some gum-like substance comes out of it. So, what is that? That is waste, brother. That is waste. But it is useful to us. That's a different matter.

Okay, name one gaseous and one non-gaseous waste product excreted by a plant. A gaseous product of the plant is CO2 or oxygen, whichever you write. Right? Because it releases oxygen during photosynthesis. And non-gaseous. You can say anything non-gaseous. Gums, resins, right? We can write anything. Okay? Resins, latex, gums, excess water, organic acids. Any of these.

Finally, friends, this chapter ends here. But what was the most important part of this chapter? Understand. Don't forget the heart I explained. Don't forget it. Right? Put some pressure on your mind once again and say, what was it? PV Sindhu said "Ayyo." What did she say? "Ayyo." What did she have to do? She had to video call. Right? Whom did she have to call? Her family. What did she say? Yes. Yes, she told PA. So, remember that. Pulmonary vein, aorta, vena cava, and finally, pulmonary artery. That flow is very important. All the questions that could be asked, I have asked them all. I can guarantee that this is one of the best one-shots. Nothing outside this will come in your exam. It won't come. This is PK Bhaiya's word. Right? It has value. Okay? And whenever you feel demotivated, remember one thing, friends, there was a great basketball player. I saw an interview of his, and he said one line, you know, the day before a basketball match, what do I do? I imagine myself scoring. I imagine myself making baskets, making baskets. I just imagine. Because power lies here. In your mind. Your powers. If you feel that your exam marks will not be good, then they will not be good. But if you feel that you will score excellently, then you will. Power is here. Power is here. Remember. And with this, we conclude this lecture. Smile, always hide your sorrow. Time will tell those people who we are. And our time has come to prove all those people wrong. I am your own Prashant Bhaiya. If you liked the lecture, the Instagram link is below. Put it in your story and let me know because I cannot see messages. But if you put it in your story, I can see it. You liked it. Message me and tell me. Comment and tell me. Also, tell me which lecture you want next. Bye.