Question

Amino acids are structural units of:

Hint:

Proteins are polymers of amino acids linked by peptide bonds; they are essential biomolecules for structure and function of living cells.

Answer 1

Step 1: Understanding amino acids.
Amino acids contain both an amino group (-NH$_2$) and a carboxyl group (-COOH). They are the building blocks of proteins.

Step 2: Protein structure.
Proteins are long chains of amino acids linked by peptide bonds. Each protein has a unique sequence of amino acids that determines its structure and function.

Step 3: Analyzing the options.
- (A) Carbohydrates: Built from monosaccharides, not amino acids.
- (B) Proteins: Correct. Proteins are polymers of amino acids.
- (C) Lipids: Composed of fatty acids and glycerol, not amino acids.
- (D) Vitamins: Organic micronutrients, not polymers of amino acids.

Step 4: Conclusion.
Therefore, amino acids are structural units of proteins.

Final Answer: \[ \boxed{\text{(B) Proteins}} \]