Protein is an essential nutrient

Protein is one of the nutrients along with carbohydrate, fat, vitamins, minerals, and water. The source of all of these nutrients is good. Some foods contain much higher amounts of specific nutrients than others and sometimes we refer to certain foods as “protein foods”.

It is important to realize that all goods contain more than one nutrient and most foods contain substantial amounts of several nutrients. For example, meat, which is a good source of protein, carbohydrate, fat, riboflavin and calcium.

Protein is an essential nutrient. There is no life without protein. Protein is contained in every part of your body, the skin, muscles, hair, blood, body organs, eyes, even fingernails and bone. Next to water, protein is the most plentiful substance in your body.

Structure of Proteins

Proteins are composed of small units. These units are the amino acids which are called the building blocks of protein. There are about 20 different amino acids which are commonly known.

Each different protein is composed of various amino acids put together in varying order with almost limitless combinations. Most proteins are large molecules that may contain
several hundred amino acids arranged in branches and chains.

Functions
Protein has a critical physiological function. Protein is primarily used in the body to build, maintain, and repair body tissues. In the event that protein intake is greater than that required by the body for this primary function, excessive protein is converted to energy for immediate use or stored in the body as fat. Protein energy will be used only after other energy sources (carbohydrate and fat) are exhausted or unavailable.

See the Video, given by

Lecture Series on BioChemistry I by Prof.S.Dasgupta, Dept of Chemistry, IIT Kharagpur.

Lecture Video I

Lecture Video II

Lecture Video III

Lecture Video IV