I weigh approximately 80 kilograms. Most of it is water, or about 64 percent, although this cannot be seen from sight. I mean, compared to other living things, I like to think I'm fairly solid. Proteins are second only to water, about 16 percent. Not only in muscles, but also in the small sodium and potassium pumps present in neurons In hemoglobin in the blood and in enzymes that stimulate chemical reactions In each of the 37 trillion cells in the body. Fat is 16 percent of my body, and this does not bother me at all. Mineral salts such as calcium and phosphorus in the bones and iron in the blood constitute 4 percent.
Starches are one percent, and most of them are consumed while talking to you Or store it as glycogen pending its use. This does not mean that I ate 80 kg of food and it became like this. Rather, my body constantly acquires substances, such as yours, that extract some of them to store it Burns others to get energy, and gets rid of the rest. But even things stored in the body do not last forever. Some of the chemicals that I gain from food eventually become part of my body, But the enzymes wear off, the membranes break down, and the nuclear acids are oxidized, so we lose them. Then I need more of those chemicals to make up for the lost ones. As a result, during my lifetime my body cells will be created Between 225 and 450 kg of protein. That is, three, four or five homologous copies made of protein only. All proteins, fats, carbohydrates and nuclear acids That makes up my body comes from food, of course.
Every living being must continue to earn and break down food In order to continue to supply himself with the raw materials he needs to survive. All this activity requires energy that we get from food as well. So how do our bodies convert what we eat into energy and raw materials? The answer lies in an endless series of interactions devoted to doing two necessary things And completely contradictory. A group of chemical reactions destroy the reactants given to them Turning large, complex materials into molecular remains, Another group reassembles these residues into new and larger products It is assembled again to form the human body. Our bodies constantly reinvent themselves in a permanent state of loss but they are constantly rebuilding. Although all this happens at the cellular level, its results are much greater.
In these two sets of interactions, everything we have learned so far is evident For the digestive system, endocrine system, circulatory system and respiratory system. Together, these processes make up the metabolism. The scientific word "metabolism" has made sense in popular culture, But metabolism is not just about one thing. People talk about metabolism in the sense that how quickly the body burns the fuel in food, Or how high the level of personal energy. This is fine for personal trainers and fitness magazines. But functionally, the metabolism describes every biochemical reaction that takes place in the body.
More importantly, it reconciles two opposing chemical processes Always running simultaneously in the body. Anabolism is one of two chemical forces. Anabolic reactions build things and consume energy. These are the processes that take building elements present in food Such as monosaccharides, fatty acids and amino acids and convert them into larger and more complex polymers Like starches, fats and proteins that are used in cells. And when you need new building blocks or you need to release some energy Polymers present in the body or new polymers present in the food are broken down by catabolic reactions.
Undermining processes break larger molecules. And when their bonds are broken, they produce the energy needed to stay warm and move, and fuel cells To rebuild those polymers. The metabolism process is very similar to the "Sisyphus" of myths. She works hard but never ends. And the rock that instance of Sisyphus pushes you up to the top of the summit to see it fall again, They are the nutrients, which are the molecules that are always destroyed by the body and then rebuilt To be destroyed again.
These nutrients or substances that the body needs to build, maintain and repair itself It has six basic groups. In terms of volume, water makes up most of what we consume and what our bodies make up. So it's probably the most important nutrient. Then there are vitamins, which are compounds found in fat-soluble or water-soluble forms. They are not used as building blocks or for energy production. But it is essential in helping the body use other nutrients that do this. For example, vitamin C improves absorption of iron and vitamin K important for blood clotting, Some B vitamins are important for producing adenosine triphosphate from glucose. And minerals, like vitamins, do not provide fuel, but have various other functions.
Calcium, magnesium and phosphorus strengthen bones and teeth, and iron is important in the formation of hemoglobin. Potassium, sodium, and chlorine help maintain the body’s pH balance, It is used in action efforts. So water, vitamins and minerals are essential. But the essential nutrients that everyone talks about What we find on the various food labels are carbohydrates, fats and proteins. Most of the carbs we eat in our lives, With the exception of the lactose present in milk, it originally comes from plants. Monosaccharides come from fruits, honey, sugar beets, and cane sugar, While starch polysaccharide comes from vegetables and grains. And what you should know is that monosaccharide glucose is the most important molecular fuel What cells need to make adenosine triphosphate. Adenosine triphosphate is the molecule that cells use to stimulate anabolic reactions When you need to produce new polymers or do anything else, run the sodium and potassium pump Or separate the head of the myosin thread in order for a muscle to contract. But adenosine triphosphate is unstable, hindering its storage, so cells store energy in the form of glucose, It can then undermine it and convert it into adenosine triphosphate when you need it.
Some cells can get energy from fat. But most important cells like neurons and red blood cells use only glucose, So most of the starches absorbed by the intestine turn into glucose for this reason. But if there is no immediate need for energy, it can be stored as glycogen in the liver or muscles Or converted to glycerol and fatty acids to produce triglycerides. Although there appears to be an advertising war waged against nutritional fats, However, we definitely need it.
Fat in fat tissue stores energy, of course, but it stores fat-soluble vitamins Members are assigned. Myelin generates myelin that isolates neurons in the brain and body As well as the skin's fat layer, and provides the necessary caloric content found in breast milk. But there are other important lipids, such as cholesterol, which are the basis of compounds Like the male hormone and estrogen. Phosphorous lipids, which make up the cell membrane In nearly every one of the 36 trillion cells in the body. If you like to eat meat, it may be the source of many of the fats you digest. But plants also contain fats. Plants use lipids to store energy just like a human being, But it stores them in fruits, nuts and seeds, and this is similar to the milk of plants, That is, it is food for her young.
Either way, when you eat fat, the triglyceride breaks down and turns it into glycerol And fatty acids. These molecules can then be treated and used to make adenosine triphosphate, Or they can be converted to other types of citrus fats, which the cells can reassemble To become triglycerides and phosphorous lipids. The liver does an excellent job in converting acidic acid to another acidic fat, But there are types that he cannot create. For example, omega-6 and three fatty acids are called essential fatty acids Because the body cannot make it, so it must be eaten. It is converted to various types of useful molecules, such as those used to make neural networks in the brain As well as to give the signal to start inflammation during the healing process. But if starches give energy and fat isolates and stores energy, Because proteins do everything else.
They form the bulk of the muscles and connective tissue, which is the substance that creates ion channels and pumps In neurons and muscle cells, you make enzymes It is responsible for almost every chemical reaction in the body. This means that the body acts on proteins, and virtually everything is made of protein. In terms of food, meat, dairy products, eggs, legumes, nuts, and grains, All are rich in protein.
But because everything we eat was alive in the past, And because every cell of every living being contains protein, as long as you eat whole foods, You at least partially re-supply yourself with protein. It may seem that you have to eat muscles to make muscles, or eat enzymes to make enzymes, But the process does not take place like this. Since all proteins are made from only 20 amino acids, The differences between thousands of unique proteins are simply found in the sequence of those amino acids.
And of course, you have a nanoparticle that knows exactly which amino acids it will synthesize together In any order to make a specific protein. It is called DNA. For example, when you eat hamburgers, the actin protein in the meat is destroyed It breaks down into its components, which are amino acids, which mix with other amino acids Other proteins in the meat include collagen, elastin, titin and myosin In addition to all the proteins from bread, tomato and mayonnaise.
These amino acids are regrouped using anabolic reactions To become your own proteins, but somewhat different depending on what your nucleic acids determine. Each cell is like a picky chef and must have every amino acid you need That is, each element must be present before you even consider starting to make protein. And just like grease, cells can improvise And the conversion of some amino acids to other amino acids if it lacks an element. But there are nine essential amino acids that you cannot make from other amino acids and you must eat them. Not all foods provide every essential amino acid, but when you mix foods, Like grains, rice, or pasta and cheese, you get all the essential amino acids. This is important because after water, the body is made up of proteins at about 16 percent.
But what about the one percent in the body? Starches? How does that small part of the body make all the energy? This is what we will discover next time. But today you learned everything about the necessary nutrients, including water, vitamins and minerals Carbohydrates, fats and proteins, as well as how anabolic reactions do By building structures and consuming energy, while delegated reactions destroy things and give energy. These two competing forces make up the remarkable paradoxical process known as metabolism.
Thank you to Education Officer Linnea Boyev and thanks to all of our Patreon patrons Who make Crash Course content possible through their monthly contributions, not just for themselves But for everyone everywhere. If you love Crash Course And you want our help to keep making great videos like this, visit patreon.com/crashcourse. The episode was filmed in studio d. Sheryl C. Kenny of Crash Course. This episode was written by Kathleen Yale, edited by Blake de Pastino, and our consultant is Dr. Brandon Jackson. It was directed by Nicholas Jenkins and edited by Nicole Sweeney Our sound designer is Michael Aranda, and our graphics team is Thought Café.