Biological macromolecules refer to various organic molecules with molecular weight of tens of thousands or more as the main active components in organisms. Common biomacromolecules include protein, nucleic acids, lipids and sugars.

Relationship between glucose metabolism and lipid metabolism

To be clear, the transformation between sugar and fat is two-way, but the degree of transformation is different. Sugar can form fat in large quantities. For example, when yeast is cultured in a sugar-containing medium, fat can be produced in cells, and the fat synthesized by a single species of yeast can be as high as 40% of the dry weight of the yeast. However, fat cannot be converted into sugar in large quantities. For example, when some animals hibernate, fat can be converted into sugar.

Relationship between carbohydrate metabolism and protein metabolism

Firstly, the concepts of essential amino acids and non-essential amino acids are defined: the so-called non-essential amino acids refer to amino acids that may be synthesized in human cells; The so-called essential amino acids refer to amino acids that cannot be synthesized in human cells. There are eight essential amino acids for human body, namely lysine, tryptophan, phenylalanine, leucine, isoleucine, threonine and methionine. Then it should be pointed out that the transformation between sugar and protein can also be two-way: the intermediate products of sugar metabolism can be transformed into non-essential amino acids, but sugar cannot be transformed into essential amino acids, so the process of transforming sugar into protein is not comprehensive; However, almost all natural amino acids that make up protein can be converted into sugar after deamination. For example, if dogs with artificial diabetes are fed with protein, more than 50% of protein can be converted into glucose.

Relationship between protein metabolism and lipid metabolism

The transformation between protein and lipids varies from organism to organism. For example, it is not easy for humans and animals to synthesize amino acids from fat, while plants and microorganisms can produce amino acids from fatty acids and nitrogen sources. Some amino acids can also be converted into glycerol and fatty acids in different ways. For example, by feeding animals food containing only protein, animals can accumulate fat in their bodies.

The metabolism of sugar, protein and lipid are mutually restricted.

Sugar can be converted into fat in large quantities, but fat can't be converted into sugar in large quantities. Only when sugar metabolism is disturbed can energy be supplied by fat and protein. When the intake of sugar and fat is insufficient, the decomposition of protein will increase. For example, when the glucose metabolism of diabetic patients is impaired, energy is broken down by fat and protein, so the patients show emaciation.