Question

What are the characteristics of proteins?

Answer 1

Hint: Proteins are a kind of nutrient that help in repairing and replacing wounded tissues of the body. They also contribute to building up healthy muscles. Proteins are one of the basic nutritional requirements for the human body.

Complete answer
Following are few of the characteristics of proteins:
Structure: Amino acids are nothing but collections of amino acids. Therefore, their structure is majorly decided by the pattern of arrangement of these amino acids. These amino acids are bonded together by hydrogen bonds. Their structure is highly determined by their location in the body of the organism. Such as hairs have fibrous protein as it has long chains of amino acids.
Solubility: Protein's solubility depends upon its structure. The three dimensional proteins are soluble in water. However, denaturation (change in molecular structure) of these proteins can reduce their solubility. While chained proteins such as fibrous proteins are insoluble.

Strength: It is another prime quality of protein. Strength of any organism is determined by its muscles which are maintained by proteins. Therefore, we can say that proteins have high strength as they are made up of hydrogen bonds at molecular level which is one the strongest bonds.
Stored energy: Unlike carbohydrates and fats, proteins are not concerned with energy production processes. Their prime role is to contribute to growth and repair of tissues. However, in some conditions they can also be burnt by the body to produce energy. $20\%$ of the daily calorie quota is served by proteins only.

Note:
Proteins are one of the most important nutrients required by a healthy body. They contribute to growth and maintenance of tissues along with maintaining body structure and pH level. Besides, it boosts immunity of the body and also initiates various kinds of biochemical reactions in the body.