[Edit this paragraph] protein's physiological function.
1. Construct the human body: protein is the material basis of all life, an important part of body cells, and the main raw material for the renewal and repair of human tissues. Every tissue of the human body: hair, skin, muscles, bones, internal organs, brain, blood, nerves, endocrine and so on. Are made up of protein, so diet makes people themselves. Protein is very important to human growth and development.
For example, the characteristic of brain development is to complete cell proliferation at one time, and the growth of human brain cells has two peaks. The first is when the fetus is three months old; The second is the period from birth to one year old, especially 0-6 months, when brain cells grow violently. By the age of one, the proliferation of brain cells is basically completed, and its number has reached 9/ 10 of that of adults. Therefore, 0- 1 year-old children have unique intake requirements for protein, which is particularly important for children's intellectual development.
2. Repair human tissues: The human body is composed of 10 trillion cells, which can be said to be the smallest unit of life. They are in an endless process of aging, death and rebirth. For example, the epidermis of young people is updated once every 28 days, while the gastric mucosa is completely updated in two or three days. Therefore, if a person has a good intake, absorption and utilization of protein, his skin will be shiny and elastic. On the contrary, people are often in a sub-health state. Tissue damage, including trauma, can not be repaired in time and with high quality, which will accelerate the decline of the body.
3. Maintain normal metabolism and transport of various substances in the body. Carrier protein is very important for maintaining normal life activities of human body. Can carry all kinds of substances in the body. For example, hemoglobin transports oxygen (the renewal rate of red blood cells is 2.5 million/sec), lipoprotein transports fat, receptors and transporters on cell membranes.
4. Albumin: Maintain the balance between osmotic pressure and body fluids.
5. Maintain the acid-base balance of body fluids.
6, immune cells and immune proteins: there are white blood cells, lymphocytes, macrophages, antibodies (immunoglobulin), complement, interferon and so on. It is updated every seven days. When protein is abundant, this unit will be very strong. If necessary, it can be increased by 100 times in a few hours.
7. Various enzymes that constitute the basic catalytic and regulatory functions of human body. There are thousands of enzymes in our body, and each enzyme can only participate in one biochemical reaction. There are more than 100 biochemical reactions in human cells every minute. Enzymes can promote the digestion, absorption and utilization of food. If the corresponding enzymes are sufficient, the reaction will proceed smoothly and quickly, and we will be full of energy and not easy to get sick. Otherwise, the reaction will slow down or be blocked.
8, the main raw materials of hormones. It can regulate the physiological activities of various organs in the body. Insulin is synthesized by 5 1 amino acid molecule. Auxin is synthesized by 19 1 amino acid molecule.
7. It constitutes neurotransmitters such as acetylcholine and serotonin. Maintain the normal functions of the nervous system: taste, vision and memory.
8. Collagen: It accounts for 65,438+0/3 of protein of the body, generates connective tissue and forms the bones of the body. Such as bones, blood vessels and ligaments. , determine the elasticity of the skin and protect the brain (a large part of brain cells are collagen cells, forming a blood-brain barrier to protect the brain)
9. Provide heat energy.
[Edit this paragraph] The role of protein
Protein plays a very important role in the life activities of cells and organisms. The structure and characteristics of organisms are related to protein. Protein is also involved in the regulation of gene expression, intracellular redox, electron transfer, nerve transfer, learning and memory and other life activities. Protein is the main enzyme that plays a catalytic role in various biochemical reactions in cells and organisms. Many important hormones such as insulin and thymosin are also protein. In addition, there are many kinds of protein, such as protein in plant seeds (beans, peanuts, wheat, etc.). ) and protein in animal protein and cheese are all used for biological nutrition growth. Some protein, such as snake venom and bee venom, are weapons for animals to attack and defend.
Protein and health.
Protein was discovered by the Dutch scientist Gerrit in 1838. He observed that living things could not exist without protein. Protein is an extremely important polymer organic matter in living organisms, accounting for 54% of the dry weight of human body. Protein is mainly composed of amino acids, and various types of protein are formed due to different combinations and arrangements of amino acids. It is estimated that there are more than 654.38+ million kinds of protein in human body. Life is an advanced form of material movement, which is realized through protein, so protein has extremely important biological significance. The growth, development, movement, heredity, reproduction and all other life activities of the human body are inseparable from protein. Life movement needs protein and protein.
Globular proteins (tertiary structure) Some physiologically active substances in human body, such as amines, neurotransmitters, polypeptide hormones, antibodies, enzymes, nuclear proteins and protein, which plays a "carrier" role in cell membrane and blood, are inseparable from protein. protein plays an extremely important role in regulating physiological functions and maintaining metabolism. The composition of muscles in human exercise system and the metabolism of muscles in the process of contraction, doing work and completing actions are all related to protein. Without protein, physical exercise is impossible.
In biology, protein is interpreted as a polypeptide formed by the connection of amino acids through peptide bonds, and then a substance formed by the connection of polypeptides. To put it bluntly, it is the scaffold and main substance that constitutes human tissues and organs, and plays an important role in human life activities. It can be said that there would be no life activities without protein. Protein mainly exists in lean meat, eggs, beans and fish in daily diet.
Protein deficiency: Adults: muscle wasting, decreased immunity, anemia, and severe edema. Minors: growth and development stagnation, anemia, poor intellectual development and poor eyesight. Protein overdose: protein cannot be stored in the body, nor can it be absorbed by the body. Excessive intake of protein will lead to protein poisoning and even death due to metabolic disorder.
[Edit this paragraph] Essential amino acids and non-essential amino acids
Protein in fibrous protein (secondary structure) food must be digested by gastrointestinal tract and decomposed into amino acids before it can be absorbed and utilized by human body. What the human body needs for protein is actually the need for amino acids. The absorbed amino acids can only meet the needs of the human body in quantity and variety, and the body can use them to synthesize its own protein. Amino acids are divided into essential amino acids and non-essential amino acids in nutrition.
Essential amino acids refer to amino acids that the human body can't synthesize or the speed of synthesis can't meet the needs of the human body and must be ingested from food. For adults, there are eight kinds of amino acids, including lysine, methionine, leucine, isoleucine, threonine, valine, tryptophan and phenylalanine. Histidine and arginine are also essential amino acids for infants.
Non-essential amino acids do not mean that the human body does not need these amino acids, but that the human body can synthesize them by itself or transform them from other amino acids without directly taking them from food. These amino acids include glutamic acid, alanine, glycine, aspartic acid, cystine, proline, serine and tyrosine. Some non-essential amino acids, such as cystine and tyrosine, can also save the requirements of methionine and phenylalanine in essential amino acids if they are supplied adequately.