Life Sciences

This article focuses on the core question of "Why do we still need to eat dietary fiber that cannot provide energy?" It introduces the current situation of rising incidence of diseases such as overweight, obesity, diabetes, hypertension, hyperlipidemia, myocardial infarction, and stroke in the context of modern agriculture and food industry development. It explains that although dietary fiber cannot provide energy for the human body, it has multiple benefits, including producing a feeling of fullness to help with weight loss, promoting gastrointestinal motility to prevent constipation, reducing the risk of colorectal cancer, and promoting the growth of beneficial intestinal bacteria. Therefore, it is called the "seventh nutrient" in addition to the six major nutrients of protein, fat, sugar, vitamins, water, and inorganic salts. It also explains from an evolutionary perspective the root cause of related diseases caused by the reduction of dietary fiber in modern diets, and points out that re-emphasizing the role of dietary fiber is a return to the natural state of the past.

This article begins with the example of Liu Chunhong breaking the world record in weightlifting at the 2008 Beijing Olympics, and then explains why glucose is the most important energy source in the human body. It compares the energy-supplying characteristics of fat and glucose, introduces the energy-supplying mechanism of glucose, the reasons why the human body needs to control blood sugar concentration, and the three backup methods used by the human body to ensure the energy supply of muscles

This article explains why the vast majority of plants, except for a few such as the Venus flytrap, do not "eat" things. It points out that plants obtain energy from sunlight, which can be absorbed by chlorophyll in their bodies. They break down water into hydrogen and oxygen, use hydrogen to synthesize ATP, and combine it with carbon dioxide to produce sugars. Then, they further synthesize the various molecules they need, such as proteins, fats, and vitamins. They can grow and reproduce solely by relying on sunlight, air, water, and fertilizers in the soil, making them self-sufficient autotrophic organisms that do not need to obtain energy from other organisms or acquire "parts" for building and repairing their bodies like heterotrophic animals.

This article focuses on the question of "why all animals need to eat", explaining that animals need to eat because food can not only provide energy for various life activities, but also provide the necessary substances for the body's metabolism and the repair and renewal of components, thus maintaining the continuity of life.

This article focuses on the question of "why HeLa cells are immortal", and introduces that HeLa cells, which originated from the uterus of a 31-year-old woman in the United States in 1951, are cancer cells that can divide and proliferate indefinitely. They are used as model cells for cancer research in many laboratories around the world. The core reason for their immortality is that the telomerase in the cells can replenish the telomeres that shorten due to the loss of bases during cell division, maintaining the length of the telomeres. Therefore, telomerase is also called the "immortality enzyme" by many biologists.

This article focuses on the question of "Is there a 'life clock' in the human body?" and introduces the definition and structural characteristics of telomeres, which are known as the "life clock" of the human body, as well as the relevant research conclusions on the shortening of telomeres during cell division and its connection with cell aging and the human lifespan limit.

This article focuses on the question of "how long can humans live?" and introduces the changes in the average lifespan of Chinese people, the age classification standards of the World Health Organization, and two methods of estimating human lifespan, namely the growth period multiplication method (estimating human lifespan to be 100 to 175 years) and the Hefley limit method (estimating normal human lifespan to be 120 years).

This article focuses on the topic of "why clownfish are 'hermaphrodites'," introducing the clownfish's symbiotic living habits with anemones, their strict population hierarchy, and the unique physiological phenomenon of gender conversion. It also mentions other hermaphrodite animals such as earthworms, and speculates that the phenomenon of hermaphroditism in the animal kingdom may be related to natural selection caused by individuals of the same sex competing for mating opportunities, which is beneficial for species reproduction and population increase.

This article introduces the characteristics, differences, and suitable environments of asexual and sexual reproduction in hydras by describing the process of Abraham Werner discovering hydras and their reproduction methods. It also explains why hydras can both be "fathers" and "mothers".

This article focuses on the question of "why some people worry that men might become extinct", introducing the origin and evolution of the Y chromosome, as well as the different academic viewpoints of various scholars on the defects of the Y chromosome, its extinction time, and its self-repair ability.

This article focuses on the question of "whether there are other genders besides male and female in humans", introduces the role of sex chromosomes in determining human gender, and lists various abnormalities in sex chromosome composition, such as X0 type, XXX type (super-female), XXY type, XYY type (super-male), and YY type, along with their corresponding physical development, intelligence, personality, and other characteristics.

This article focuses on the question of "why the gender of a child is determined by the father", introducing the composition of human chromosomes, the definition of autosomes and sex chromosomes, the process of meiosis in producing sperm and eggs, explaining that female eggs only contain X sex chromosomes, while male sperm contain either X or Y sex chromosomes. The combination of the sex chromosomes after fertilization determines the gender of the fetus. The testis-determining gene on the Y chromosome prompts the fetus to develop into a male, thus the gender of a child is determined by the father.