Which macromolecule provides raw materials for growth and the repair of body structures?

• A. Carbohydrates
• B. Proteins
• C. Lipids
• D. Vitamins

Answer: (B)

Proteins provide the building blocks the body uses to grow and repair tissues. They’re made of amino acids, which are obtained from dietary proteins and then used to synthesize new proteins that replace damaged cells, build muscles, skin, cartilage, and connective tissue, and produce essential enzymes and structural components. While carbohydrates and lipids mainly supply energy and storage or membranes, the raw material for growth and repair at the structural level comes from amino acids in proteins. Vitamins play important supporting roles as cofactors, but they aren’t the macromolecules that supply the actual growth-building blocks.