There is still a long way to go in understanding life

Explore, let human beings live healthy, happy and quality lives

Liu Ying, a professor at Peking University's School of Future Technology, said: "I am very interested in life. I am curious about what is going on inside the human body all the time, and I want to understand ourselves."

Liu Ying specializes in cell biology, studying human metabolism and aging. "Cells are the most basic structural and functional units that make up life. Life is too complex, let's first study the things inside the cell. Study how a cell senses changes in its environment, changes in the levels of energy or nutrients it can use. When we eat a full meal, proteins break down into amino acids, and cells sense these nutrients and cleverly start anabolism, storing up our excess, surplus nutrients. When the cells are hungry, they sense the lack of energy and material in the environment and break down what they have stored to provide energy."

Liu believes it is crucial to study how cells adapt to their surroundings. "Many cancer cells can also continue to grow in an environment with limited nutrients, resulting in excessive cell proliferation and division. So when we do research, we find that some genes are closely related to the development of cancer. In addition, changes in the metabolic state of cells are also closely related to aging. "It's very interesting that people can slow down aging with moderate caloric restriction."

In 1865, Mendel published the hypothesis of the law of inheritance based on the pea hybridization experiment, and genetics was born. Subsequently, genetics and evolution combined to give birth to molecular biology, recombinant DNA technology. In 1990, the Human Genome Research Project was launched. By 2003, scientists had completed the determination of all 3 billion pairs of base sequences of the human genome, and life science was believed to have entered the era of post-genome and proteomics.

It took more than 100 years for human beings to complete the description of the whole face of the genome, which changed our view of life, so that we can rethink what life is, and see a clearer new picture of life.

But human beings are still powerless over "life" in many cases - from cell research to the entire field of life sciences, the understanding of life is still based on limited genetic information. Scientists have crossed the barrier of limited genomes in an attempt to uncover why life behaves in an infinite way of development and differentiation.

"Some time ago, I saw a video where someone said that the science of life is now 90 percent of the way to understanding life." Professor Yang Maojun of the School of Life Sciences at Tsinghua University does not agree: "According to my personal understanding and the law of scientific research, the cognition of life science is still in its infancy and cannot be quantifiable." If I had to quantify it, I'd say less than 1%. Knowledge is like a point, with the accumulation of knowledge, as the point expands into a circle, the more unknown knowledge outside the circle is exposed to, unknown knowledge is infinite, but the knowledge we know is limited, compared with infinite, I really can not define the extent of our understanding of life."

So what can the life sciences do for us? Yang Maojun said that the question should be asked, what do we humans want the life sciences to do for us? "A healthy, happy and quality life, of course. The development of life science in these years is obvious to all. Take the average life expectancy of China's population as an example, it was 35 years old in 1949, 57 years old in 1957, 68 years old in 1981, 75 years old in 2010, and 77.3 years old in 2019. In the past, we often said that life is rare in the past 70 years, and now the elderly over 70 years old are everywhere. This is the most intuitive manifestation of the rapid development of life science in China over the years."

The challenge is that the understanding of how living organisms work is far from sufficient

Scientific research is always exploring the "unknown", but often there are still many "unknowns" in the "known".

In Liu Ying's view, the more research in the field of life science, the more reverence for life, "life is really very subtle, you can't imagine how it can be so smart, so subtle to regulate every step."

But "the more I study, the more I know about life, the more ignorant I find myself," and "some conventional concepts or phenomena have been constantly revised and improved in recent years."

For example, the Warburg effect suggests that cancer cells provide energy and produce lactic acid primarily through glucose degradation (breaking down glucose). But this way of providing energy, it produces very little energy. Because most normal cells get more than 90% of their energy from mitochondria.

Why do cancer cells go through this pathway of sugar degradation? According to Liu Ying, the previous interpretation believed that when cancer cells grow into a large tumor, many cells are crowded together, especially the cells in the middle of the tumor, and cannot access too much oxygen, so there is no way to use mitochondria to provide energy.