Protein is an important part of all cells and tissues. Various components of human and animal bodies, such as organs, muscles, skin, blood and plant seeds, are mainly composed of protein. In most cells, protein accounts for more than 90% of cell dry matter. Even the simplest single-celled organisms, such as E.coli, each cell contains an estimated more than 3,000 species of protein. Protein is not only an important part of organisms, but also plays an extremely important role in life activities. Life activities such as exercise, respiration, nutrient transport, nerve conduction, thinking and memory are mainly realized by protein, and the metabolism of life is also carried out under the catalysis of a special protein-enzyme.
The cells of all living things contain not only protein, but also nucleic acids. Nucleic acid is the carrier of life genetic information, which plays a vital role in the growth, heredity and variation of life. Moreover, the process of synthesizing protein in organisms can only be completed with the participation of nucleic acids.
In other words, protein and nucleic acid constitute the material basis of life, and life activities are essentially the embodiment of protein and nucleic acid movement. It can be said that the essence of life lies in the microscopic movement of organisms at the molecular level.
Discovery of nucleic acid
Swiss biologist Michelle discovered nucleic acid. 1868, he used pus cells on surgical bandages as materials to separate an acidic substance containing phosphorus from the nucleus. Because this substance originated from the nucleus, it was named nuclide. In fact, nuclide is a complex of nucleic acid and protein.
During the period of 187 1- 1873, Michel further proved that the nucleus is mainly composed of a phosphorus-containing substance, not protein, and was later named nucleic acid, which means "an acidic substance found in the nucleus".
Molecular machines operates in an orderly manner.
Protein and nucleic acid molecules are composed of thousands or even hundreds of thousands of atoms, which are called biological macromolecules. Every biomacromolecule can be regarded as the molecular machines of life. All life activities are regulated by molecular machines, and the structure of molecular machines is complex and orderly. Besides protein and nucleic acid, these molecular machines also include some other biomacromolecules or macromolecular groups, such as sugars, lipids and biomacromolecule complexes. It is precisely because of the orderly operation and coordination of many molecular machines in the micro-world of life that life has vitality.
Open molecular machines and have a look.
During the period of 1968, a very serious viral influenza occurred in Hong Kong, and there was no effective treatment at that time. Twenty years later, the researchers measured the molecular structure of protein in the shell of influenza virus, and also measured the structure of the compound formed by protein combining with a molecule in human body, which is the reason why people are infected by the virus. After understanding the structure of these molecules, the researchers synthesized a special antiviral drug by artificial method, which can combine with virus protein to prevent the virus from infecting human cells, thus preventing this influenza infection.
This example shows that once we understand the structure of biological macromolecules, our understanding of life functions will be greatly deepened.
The atoms that make up biomacromolecules are mainly hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur and a small amount of metal atoms. Each atom has a specific three-dimensional spatial arrangement in macromolecules and occupies a specific position in space. The types of atoms that make up a biomacromolecule and the interaction between each atom and electrons determine what kind of life function this biomacromolecule performs, that is, the structure of biomacromolecule and its relationship with function are the starting points to reveal the essence of life. By measuring the structure of biomacromolecules and analyzing the relationship between structure and function, we can understand the function of biomacromolecules, and we can also understand or estimate the biological function of unknown biomacromolecules by comparing them with known biomacromolecules. For example, the mechanism of photosynthesis is the mystery of life that scientists all over the world have been trying to reveal. 1987, scientists first measured the three-dimensional structure of the photoreaction center, the core mechanism of plant photosynthesis, thus revealing the secret of how solar light energy is converted into chemical energy of organic matter at the molecular level.