Protein is a kind of substance with a certain spatial structure formed by the winding and folding of polypeptide chain composed of amino acids by "dehydration and condensation".
Protein is a high molecular compound which is caused by the polymerization-amino acid binding in a certain order to form a polypeptide chain, and then by one or more polypeptide chains combining in a certain way. Protein is the scaffold and main substance of human tissue and organs. It plays an important role in human life activities. Protein is found in lean meat, eggs, beans and fish.
Protein is a complex organic compound, called "ru meet n". Amino acids are the basic building blocks of proteins. Amino acids are condensed by dehydration to form peptide chains. Proteins are biological macromolecules composed of one or more polypeptide chains, each of which contains 20 to hundreds of amino acid residues (-r). Various amino acid residues are arranged in a certain order. The amino acid sequences of proteins are encoded by the corresponding genes. In addition to the 20 basic amino acids encoded by the genetic code, some amino acid residues in proteins can also be modified after translation to change the chemical structure, thus activating or regulating proteins. Multiple proteins can work together, often by binding together to form a stable protein complex, folding or spiraling into a spatial structure that performs a specific function. The organelles for synthesizing polypeptides are the ribosomes in the cytoplasm on the rough surface endoplasmic reticulum. Proteins differ in the type, number, sequence and spatial structure of their amino acids.
The protein that feeds into the body is digested and hydrolyzed into amino acids and absorbed, and then the protein that the human body needs is synthesized again. At the same time, the new protein is continuously metabolized and decomposed, and it is in a dynamic balance at all times. Therefore, the quality and quantity of food protein and the proportion of various amino acids are closely related to the amount of human protein synthesis, especially the growth and development of adolescents, the eugenics of pregnant women and the healthy and long life of the elderly. Proteins are divided into complete proteins and incomplete proteins. Rich in essential amino acids, high-quality proteins are collectively called complete proteins, such as milk, eggs, fish, meat, etc. are complete proteins, and soybeans in plants also contain complete proteins. Protein that lacks essential amino acids or contains little is called incomplete protein, such as protein contained in grains, wheat, corn and gelatin in animal skin and bone.
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