MCQ Detailed View

Proteins are essential biomolecules that play a critical role in the structure, function, and regulation of the body’s cells, tissues, and organs. They are made up of smaller units called amino acids, which are linked together by peptide bonds to form polypeptides. A single protein may consist of one or more polypeptide chains folded into a specific three-dimensional structure that determines its function.

A polypeptide is essentially a chain of amino acids, and the sequence of amino acids in a polypeptide is determined by the genetic code carried in DNA. Proteins perform a wide range of functions in living organisms. Some act as enzymes, which catalyze biochemical reactions, while others serve as structural proteins like collagen and keratin, providing support and shape to cells and tissues. Other types include transport proteins (like hemoglobin), hormonal proteins (like insulin), and antibodies, which are crucial for immune defense.

Polynucleotides, in contrast, are the building blocks of nucleic acids such as DNA and RNA, not proteins. Oxyacetylene is unrelated, as it refers to a fuel gas mixture used in welding and cutting. Thus, the correct answer is polypeptide, highlighting the direct connection between amino acids and functional proteins.

Understanding that proteins are made of polypeptides is fundamental in biology, particularly in the study of biochemistry, cell biology, and molecular biology. It explains how genetic information is translated into functional molecules, influencing processes such as metabolism, growth, and repair in living organisms. Recognizing this structure-function relationship is essential for learning about enzymes, hormones, muscle proteins, and other critical biomolecules.