Protein

Proteins are essential, complex molecules made of long chains of amino acids that are vital for the structure, function, and regulation of the body's tissues and organs. They perform a vast array of functions, including acting as structural components (like skin and hair), catalyzing biochemical reactions (as enzymes), and supporting the immune system. The sequence of amino acids determines a protein's unique three-dimensional structure and function. 

Structure and composition

Proteins are polymers of amino acids, with about 20 different types that link together in different sequences. 

The sequence of these amino acids is determined by a cell's DNA and is referred to as the protein's primary structure.  This chain then folds into complex three-dimensional shapes (secondary, tertiary, and quaternary structures) which are crucial for its function. 

Key functions

• Structural support: They provide the building blocks for structures like muscles, skin, hair, and bones. 
• Catalysis: Many proteins act as enzymes, speeding up the chemical reactions necessary for metabolism and other cellular processes. 
• Signaling: They are involved in cell communication and can act as hormones. 
• Immune response: Antibodies are a type of protein that helps protect the body from disease. 
• Regulation: Proteins help regulate the body's functions and maintain proper pH levels. 
• Energy source: If the body lacks sufficient carbohydrates and fats, it can break down protein for energy. 

Nutritional importance

Your body can make some amino acids, but others, known as essential amino acids, must be obtained from your diet.