Science Olympiad Designer Genes Practice Exam

The correct answer identifies the essential components of DNA as adenine (A), thymine (T), guanine (G), cytosine (C), phosphates, and sugar.

In DNA, the structure is made up of nucleotides, each consisting of three parts: a phosphate group, a sugar molecule (specifically deoxyribose in DNA), and one of the four nitrogenous bases (A, T, G, or C). The bases pair specifically—adenine pairs with thymine and guanine pairs with cytosine—creating the double helix structure characteristic of DNA. The phosphate and sugar form the backbone of the DNA strand, which supports the genetic code encoded by the sequence of the nitrogenous bases.

Other options mention components that do not accurately represent DNA. For instance, proteins and fats are not part of DNA’s structure, nor is RNA, as RNA is a different nucleic acid with a different function. Enzymes, while vital for processes involving DNA such as replication, are not structural components of DNA itself. Overlap might occur between DNA and components required for its function or synthesis, but these options do not accurately describe its composition.