What is protein definition?

Proteins are complex molecules that are made up of amino acids linked together by peptide bonds. They are essential for the growth, repair, and maintenance of tissues in the body, as well as the synthesis of enzymes, hormones, and neurotransmitters. Proteins come in a wide variety of shapes and sizes, and their specific functions depend on their unique structure. The human body requires 20 different amino acids to synthesize the various proteins needed for the body to function properly. Proteins are found in many different foods, including meat, dairy, beans, nuts, and grains. The recommended daily intake of protein varies by age, gender, and activity level, but average adult requirements are around 0.8 grams of protein per kilogram of body weight.