Which term is defined as the building material of living things?

Which term is defined as the building material of living things?

• A. Protein
• B. Nucleic acid
• C. Carbohydrate
• D. Lipid

Answer: (A)

Proteins act as the building material of living things because they form most of the structural framework of cells and tissues. They are polymers made of amino acids, and their diverse shapes create the rigidity and organization needed for organs, muscles, skin, hair, and connective tissue. Collagen, keratin, and actin are classic examples of structural proteins that give tissues their strength and shape. Nucleic acids store genetic information and guide the synthesis of proteins, but they aren’t the physical building blocks themselves. Carbohydrates mainly supply energy and can contribute to structure in some organisms (like cellulose in plants) but aren’t the general structural building material. Lipids form membranes and store energy, contributing to structure in membranes and fat stores, yet they don’t provide the primary structural framework like proteins do.

Proteins act as the building material of living things because they form most of the structural framework of cells and tissues. They are polymers made of amino acids, and their diverse shapes create the rigidity and organization needed for organs, muscles, skin, hair, and connective tissue. Collagen, keratin, and actin are classic examples of structural proteins that give tissues their strength and shape.

Nucleic acids store genetic information and guide the synthesis of proteins, but they aren’t the physical building blocks themselves. Carbohydrates mainly supply energy and can contribute to structure in some organisms (like cellulose in plants) but aren’t the general structural building material. Lipids form membranes and store energy, contributing to structure in membranes and fat stores, yet they don’t provide the primary structural framework like proteins do.