Constant elements and trace elements
In the human body, according to the content of the elements, the chemical elements necessary for the human body are divided into two types: constant and trace: the major elements account for more than 99.95% of the human body weight, including oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus, potassium, 11 elements of sulfur, sodium, chlorine and magnesium. Among them, carbon, oxygen, hydrogen, nitrogen and other four elements account for more than 95% of human body weight, potassium, sodium, calcium, magnesium, chlorine, sulfur, accounting for about 4% to 5% of human body weight. Trace elements refer to some elements that are needed by the human body but are indispensable, including iron, zinc, copper, manganese, iodine, cobalt, antimony, chromium, selenium and the like. Although trace elements are low in the human body, their effects are very large. For example, zinc, this element plays an important role in a variety of physiological functions of the human body: participation in the synthesis of a variety of enzymes; accelerate growth and development; enhance the ability of wound tissue regeneration; enhance resistance. Trace elements in the human body are dissolved in the blood of the human body. If such trace elements are missing, people will get sick and even die.
a small human universe controlled by four elements
For the composition of the human body, it is said that it is composed of cells, but in the end, the human body is mainly composed of four elements occupying 99.5% of the total number of atoms, namely: hydrogen (H, 62.7%), oxygen (O, 23.8%). ), carbon (C, 11.8%) and nitrogen (N, 1.17%), which makes us have to sigh the magical power of these four elements!
So what is the power that allows these four elements to control the powerful small universe of the human body? As mentioned above, the content of oxyhydrogen is the first two, because most of the human body is composed of water (composed of two hydrogen atoms and one oxygen atom, accounting for about 60% of the weight), so we often say “no water.” There is no life.” Just like the air can hold the ball of the dragonfly round, the water also shapes the structure of each cell and the whole human body. Then, all the activities in life are carried out in the warm embrace of the water. Although carbon ranks third, it has a supreme position in the life element. It is because of its powerful bonding function, which produces the uncountable organic compounds needed for the human body to assemble the structure of the adult body. It is well known that chemical reactions between elements are carried out by the formation or cleavage of bonds between elements. A carbon atom has up to four bonding “arms”, which not only gives the carbon itself a single bond, but also The bond and triple bond and the chemical reactivity of the ring, and it can be as flexible and variable as many other elements, so our life is also called carbon-based life. As for the fourth-ranked nitrogen, it has an unplaced mission in the human body’s proteins (such as enzymes) and important components such as nucleic acids (DNA and RNA). It acts like a magic wand, activates the structure of the human body, and makes the human body have vitality. The small universe of the human body begins to interpret its own story. Of course, there are many other life elements that are supporting the operation of this small universe.
Life comes from the ocean
Maybe you will ask, there are 92 kinds of natural elements in the periodic table. Why did nature choose these four simple elements to shape our human beings? This involves the problem of the origin of our human body chemistry.
As we all know, the universe created various elements in the process of formation, and used its extraordinary power to create the planet of the earth. Then, the earth relies on itself to create the sea, a more unique element of the ocean, and finally, in the ocean, a living body with a combination of different elements is born. Although the elements are inherited from the beginning to the end, the proportions of the elements vary depending on the environment in which they are located. For example, there is no high content of He (He) in the universe, because He is an inactive element. For us, a vital body that needs vitality, it becomes useless; for example, the content in the earth. Higher silicon (Si) content is very low in our human body! This is so much worse than the carbon that is also a four-coordinate bonding method! The reason is that the four-coordinate bonding method of Si is too weak to bear the various needs of the human body for various sizes of molecules, and only fade out of the life circle! The most interesting thing is the elements in the ocean, which are so close to the components (ions) in our human body fluids, which proves that our lives are derived from the ocean.
Starting from a single cell, the living body has evolved in a long period of 3.8 billion years with all the elements in the surrounding environment (the ocean, land and sky), and finally evolved. A collection of elements that are capable of getting along with the various elements in the environment. Therefore, human beings are constantly selecting the proportion of elements in the current trial and error and elimination. This is the result of natural selection, which naturally allows humans to cultivate into a highly sensitive, efficient and powerful function. , creation tools, etc.).
At this point, maybe you are wondering if you can put all the elements in the human body together and combine them into a living body by heating and pressing. the answer is negative. However, a small fertilized egg cell (about 0.2 mm) can accomplish this task – growing into a complete living body by continuously absorbing various nutrients from the mother. This process of assembling many elements into the living body still has many mysteries, and it is still waiting for humans to continue to explore.
Human body is a chemical reaction network
From the above picture, we can see that the most essential exploration of the human body is ultimately carried out at the molecular level, and this is inseparable from chemistry. Next, we will go further and talk about the chemical reactions that take place in the body assembly.
Speaking of chemical reactions, the first chemical reaction of human contact is the combustion reaction. The blazing flame emits light, releasing heat, and the reaction is rapid and intense. In fact, the same burning reaction, or breathing, is carried out in the human body. It is the reaction of glucose, amino acids and fatty acids absorbed by the human body with oxygen inhaled by the human body. However, this burning reaction in the human body is much milder and more subtle. The reason is that there is a protein (or RNA) called enzyme (enzyme) in the body, which can realize the chemical reaction in the body temperature and body environment. Rapid and gradual, the energy is also gradually released, synthesizing energy molecules such as adenosine triphosphate (also known as adenosine triphosphate, abbreviated as ATP), avoiding the body temperature rising too fast due to the massive release of energy, causing abnormalities in the human body. the result of.
The catalytic efficiency of the enzyme is extremely high, and the catalytic reaction rate can reach 108 to 1020 times of the non-catalytic reaction rate. For example, when we chew rice (or steamed bread), we can quickly feel the sweetness because the starch in the food is in saliva. The amylase catalyzed quickly into a sweet taste of maltose and sucrose. Usually this reaction takes a while to complete in vitro.
In addition, the enzyme has a high degree of specificity, an enzyme can only act on specific substances, so each chemical reaction in the human body has a corresponding enzyme matching. There are thousands of enzymes in the human body. Because of this, in the cells filled with various substances, accurate and orderly chemical reactions can still occur. It can be said that the specific enzymes are indispensable!
In fact, the chemical reactions that take place in the body are called “metabolism.” The series of chemical reactions that take place are called “metabolic pathways”. Different metabolic pathways are connected to form a huge network of chemical reactions. This sophisticated “metabolic network” provides day-to-night activities for human life. Material and energy. Therefore, how to ensure the normal operation of the metabolic network has become a research hotspot for scientists.
Do not drive after drinking, do not drink while driving, do not be a “wine driver.” For the driver’s drinking test, the police used a non-enzymatic reaction – using a device containing potassium dichromate to detect whether the driver drunk driving. As long as the driver blows into a tube, if the orange-red material in the tube is observed to turn green, the driver can be confirmed to have drunk. The reaction only needs one step:
The reaction requires two steps. First, acetaldehyde is formed under the action of alcohol dehydrogenase. If there is no catalytic enzyme, acetaldehyde dehydrogenase, in the body, the toxic acetaldehyde will accumulate in the body, causing the body. Unwell or drunk. The person who tends to drink well is because the acetaldehyde dehydrogenase in the body has rapidly converted acetaldehyde into acetic acid with little toxicity. By comparing the different processes of oxidizing the above two ethanols to acetic acid, we can clearly understand the characteristics of the chemical reactions carried out in the human body, that is, the role of efficient and highly specific enzymes must be carried out and gradually carried out.