The primary building block (monomer) of proteins is:
a)
A nucleotide
b)
An amino acid
c)
A glucose molecule
d)
A fatty acid
The correct answer and explanation is :
Correct Answer:
b) An amino acid
Explanation:
Proteins are essential macromolecules in all living organisms, playing critical roles in structure, function, and regulation of the body’s tissues and organs. The fundamental building blocks of proteins are amino acids.
Structure of Amino Acids
Amino acids are organic compounds composed of:
- A central carbon atom (alpha carbon)
- An amino group (-NH₂)
- A carboxyl group (-COOH)
- A hydrogen atom
- A side chain (R group) that varies among different amino acids
The R group determines the unique properties of each amino acid. There are 20 different amino acids that combine in various sequences to form proteins.
Protein Formation: Peptide Bonds
Amino acids link together through peptide bonds in a process called dehydration synthesis or condensation reaction. This reaction removes a water molecule and forms a covalent bond between the carboxyl group of one amino acid and the amino group of another. Chains of amino acids form polypeptides, which fold into specific three-dimensional structures to become functional proteins.
Importance of Proteins
Proteins perform various functions, including:
- Structural support (e.g., collagen in skin and bones)
- Enzymatic activity (e.g., catalyzing biochemical reactions)
- Transport and storage (e.g., hemoglobin transporting oxygen)
- Immune response (e.g., antibodies defending against pathogens)
Incorrect Options:
- a) Nucleotide: The building blocks of DNA and RNA, not proteins.
- c) Glucose molecule: A carbohydrate monomer, not related to protein synthesis.
- d) Fatty acid: A component of lipids, not proteins.
Thus, the correct answer is b) An amino acid.