The multi-molecular system composed of nucleic acid and protein has the ability of self-renewal, replication and reaction to the outside world.
health
The official definition of health by the World Health Organization (WHO):
Health refers to a good state of physical, psychological and social adaptation, not just that you are not sick or strong.
life
The multi-molecular system composed of nucleic acid and protein has the ability of self-renewal, replication and reaction to the outside world. Although the definition of life in Introduction to Molecular Biology is like this, usually, you can tell what is alive and what is not without much effort, but when you really want to express what is life in words or words, things can't be so simple. In fact, it is extremely difficult to give a scientific definition of life, and mankind has not been able to solve this problem until now. But based on the fact that human beings are also a form of life, we have tried every means on the existing basis.
There seems to be such a possibility here. As long as we make a general summary of all kinds of phenomena shown by living things, we should be able to establish an abstract concept that can define life. People always insist on doing this, but every big new discovery will always make our previous definition problematic, so the definition of life is constantly changing. The general scientific definition given by modern biology is that life is a compound phenomenon of self-reproduction, growth and development, metabolism, genetic variation and response to stimuli. Here, any single phenomenon is not unique to living things. Flame can also metabolize and reproduce, but normal people don't think it is life. The seeds of many plants can be preserved for a long time and have no life characteristics, such as ancient lotus seeds and slow-moving animals, which may not be metabolized for a long time and will have vitality when conditions are right. When it comes to reproduction, we simply have nothing to say in the face of such things as cows and mules! The same is true of growth, and the crystallization process of many inorganic substances can show this characteristic well. The external stimulus is also obvious. For example, your computer is a very sensitive guy.
conception of history
In the process of understanding life, human beings have also had difficult thinking. In ancient Greece, the reason of exercise-whether people can understand it or not-was called "force", so the great concepts of vitality and vigor were put forward. In ancient China, people tend to call the cause of exercise "Qi", and the activity of life is of course the activity of "Qi", for example, "Since birth, it is still produced, water condenses into ice, and Qi accumulates into human beings". Like force, qi is an ambiguous concept, and different people will have different interpretations. Fire is a violent material movement, which will certainly arouse people's great concern. Therefore, some ancient people in the East believed that life came from "fire" and emphasized the metabolic process of life. In addition, China ancients discussed life in an ingenious way, that is "death". Studying life and death together in this opposition is probably a major feature of China's philosophy.
health
The official definition of health by the World Health Organization (WHO):
Health refers to a good state of physical, psychological and social adaptation, not just that you are not sick or strong.