What are proteins? Proteins are complex substances and are found in all organisms. Proteins possess immense nutritional value. Proteins take part in numerous important chemical processes. The proteins of various species differ from each other. At the level of a single organism, proteins of various organs and tissues are also different.
What are proteins and their composition?
Large protein molecules are composed of long chains of amino acids joined together by chemical bonds. Scientists detected about 20 different amino acids in proteins. Known associations between structural and functional properties of proteins are ascribed to the particularities of the amino acids entering into their composition.
What are proteins, their content and distribution?
The share of proteins in human body is considerable. Muscles, liver, erythrocytes may contain about 30 % of proteins. Much protein is found in bones, hair, other organs and tissues. Protein molecules are created in the cells by amino acid arrangement with subsequent releasing into body fluids.
What are proteins and their importance?
The importance of proteins is explained by their functions. Even small amounts of some proteins, such as enzymes and hormones, are essential for life.
- An important class of structural proteins participates in maintenance and protection of the body constitution.
- Proteins are needed for normal growth and development.
- Enzymes belong to proteins. Life is impossible without enzymes. Enzymes catalyze all metabolic processes. Enzymes take part in the creation and conversion of proteins, nucleic acids, lipids, and carbohydrates.
- Several protein hormones perform significant regulatory functions.
- Proteins are genetic regulators.
What are proteins from the standpoint of nutrition?
Plants are able to synthesize all amino acids. On the contrary, animals cannot produce some essential amino acids. Animals and humans must get some nutrients from external sources. Humans get proteins from animal and plant sources such as milk, meat, eggs, and legume seeds.
What are proteins and their intake?
The recommended daily intake of protein for adults is 0.75 g per kg of body weight. A man with normal weight should consume daily 52.5 g of protein. A normal weight woman needs 41 g of protein daily. Babies, children, pregnant, and lactating women require additional proteins for the formation of tissues and milk. Athletes and bodybuilders also need higher protein amounts. The excess of protein undergoes destruction and protein nitrogen is excreted in the form of urea. Keto acids of protein origin provide 4 Calories per gram. Starvation or inadequate dietary intake of protein leads to breaking down of tissue proteins. Protein deficiency may increase the risk of infections and other diseases.