Which macromolecule is essential for building tissue and repairing cells?

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

Answer: (A)

Proteins are essential for building tissue and repairing cells because they form the actual structural components of tissues and drive the repair processes. Proteins come from amino acids and fold into shapes that give tissues their strength and function. Structural proteins such as collagen provide the extracellular matrix that gives skin, bone, and connective tissue their framework. Other proteins like keratin strengthen hair and nails, while cytoskeletal proteins such as actin and tubulin help maintain cell shape and enable movement necessary during repair. Enzymes, which are proteins, catalyze the biochemical reactions needed to rebuild damaged tissue, and antibodies and transport proteins contribute to healing and recovery as well. Tissue repair relies on the continuous synthesis of new proteins, guided by genetic information and carried out in ribosomes, so the capacity to make proteins is at the heart of rebuilding after injury.

Carbohydrates mainly supply quick energy and can have structural roles in some contexts, but they do not serve as the primary building blocks of tissue. Lipids are crucial for membranes and energy storage, not the main material that composes tissue. Vitamins are important cofactors and helpers in metabolism, but they are not macromolecules that directly form the tissue framework.