Molecular Biology

A. DNA Structure and Properties Definition: Deoxyribonucleic acid (DNA) is a double-stranded helical molecule composed of nucleotides, each containing a deoxyribose sugar, phosphate group, and nitrogenous base (adenine, thymine, guanine, or cytosine). Explanation: DNA is the primary genetic material in most organisms, storing genetic information in the sequence of its nucleotide bases. The molecule forms a double helix through complementary base pairing (A-T and G-C) and hydrogen bonding. This structure allows for accurate replication and transmission of genetic information during cell division. DNA's stability comes from the sugar-phosphate backbone and the specific base pairing rules that maintain the genetic code. Think of it as: DNA is like a twisted ladder where the sides are made of sugar-phosphate backbones and the rungs are the complementary base pairs, with the sequence of rungs representing the genetic code. Real-world application: DNA analysis is used in forensic science to identify individuals, in paternity testing, and in medical diagnostics to detect genetic disorders.