HESI A2 Biology Practice Test 2026 – Complete Exam Prep Resource

The correct answer is DNA because it serves as the blueprint for all living organisms, containing the instructions required for growth, development, functioning, and reproduction. DNA stands for deoxyribonucleic acid and has a double-helix structure made up of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. The specific sequence of these bases encodes the genetic information that is passed from one generation to the next.

In contrast, RNA, while also involved in carrying genetic information, primarily acts as a messenger or intermediary in the process of translating the genetic code into proteins. Proteins do not carry genetic information; rather, they are the products of the information encoded in DNA. Lipids, on the other hand, are biological macromolecules that primarily serve roles in energy storage, cellular signaling, and structural components of cell membranes but do not carry genetic information. This distinction highlights why DNA is classified as the molecule that carries genetic information.