Question

The building blocks of proteins are _________

• A. Lactic acid
• B. Nucleotides
• C. Amino acids
• D. ATP

Hint:

Always associate the major macromolecules with their monomers: Proteins $\rightarrow$ Amino acids; Nucleic Acids (DNA/RNA) $\rightarrow$ Nucleotides; Carbohydrates $\rightarrow$ Monosaccharides (like glucose); Lipids $\rightarrow$ Fatty acids and glycerol.

Answer 1

The Correct Option is C

Step 1: Concept:
This question tests fundamental biochemistry, specifically the monomeric subunits that polymerize to form complex biological macromolecules like proteins.

Step 2: Step-by-step Explanation:

• Proteins are large, complex biopolymers that play crucial structural, enzymatic, and regulatory roles in all living organisms. The fundamental, repeating structural units (monomers) of all proteins are amino acids.

• During the cellular process of translation, amino acids are covalently linked together in a specific linear sequence dictated by mRNA. The bond connecting them is called a peptide bond, forming a polypeptide chain that eventually folds into a functional protein.

• Let's review the other options to understand why they are incorrect:

• Lactic acid (A) is a metabolic byproduct of anaerobic glycolysis in muscle tissue, not a structural monomer for macromolecules.

• Nucleotides (B) are the building blocks of nucleic acids, specifically DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid), not proteins.

• ATP (D) stands for Adenosine Triphosphate, which is the primary energy currency of the cell, not a structural building block for proteins.

Step 3: Final Answer:
The building blocks of proteins are amino acids.