DNA

**Description:** DNA (deoxyribonucleic acid) is structured as a right-handed double helix, composed of two complementary strands. These strands are anti-parallel, meaning that the polarity of one strand is opposite to that of the other (e.g., if one strand has a 3' end at a particular end of the molecule, the other strand will have a 5' end at the same position). The double helix is stabilized by hydrogen bonds between the nitrogenous bases of the two strands, contributing to the overall stability of the DNA molecule. **Importance of DNA:** DNA is essential for all living organisms, carrying the genetic information that governs biological functions and hereditary traits. During cell division, the DNA in the nucleus replicates, resulting in two identical double-helix molecules and ensuring that each daughter cell receives an identical copy of the genetic material. The sequence of DNA (its primary structure) encodes instructions for protein synthesis. This information is transcribed into RNA and then translated into proteins in a process known as protein biosynthesis. DNA is found in the cell nucleus and in semi-autonomous organelles (e.g., mitochondria). **Model description:** The model represents a short segment of a DNA molecule, consisting of only 12 nucleotide pairs. The two strands are twisted into a helix and connected by hydrogen bonds formed between complementary nitrogenous bases. The sequence depicted in the model is CGCTATAATGCG and its complementary strand, CGCATTATAGCG, both written in the 5'→3' direction.