What is the structure of DNA?

• A. A triple helix of amino acids
• B. A single strand of ribonucleic acid
• C. A double helix of nucleotides
• D. A linear chain of proteins

Answer: (C)

The structure of DNA is best described as a double helix of nucleotides. This means that DNA consists of two long strands that twist around each other, resembling a twisted ladder. Each strand is made up of repeating units called nucleotides, which are comprised of three components: a phosphate group, a deoxyribose sugar, and a nitrogenous base. The two strands are held together by hydrogen bonds between complementary nitrogenous bases: adenine pairs with thymine, and cytosine pairs with guanine. This specific pairing contributes to the stability of the double helix and allows for accurate replication during cell division.

In contrast, the other options do not accurately represent the structure of DNA. A triple helix is not a characteristic of DNA; instead, it may refer to some specific types of synthetic or altered DNA structures. A single strand of ribonucleic acid (RNA) pertains to RNA, which is different from DNA both structurally and functionally. Finally, a linear chain of proteins is unrelated to the structure of DNA since proteins are composed of amino acids and function differently in the cell, largely serving in various roles such as enzymes, structural components, and signaling molecules. Thus, the description of DNA as a double