NATS 1575 Lecture Notes - Lecture 22: Guanine, Dna Replication, Nuclear Dna
Document Summary
Chapter 9 - dna: the indispensable forensic science tool. Portions of the dna structure are as unique to each individual as fingerprints. The gene is the fundamental unit of heredity. Each gene is actually composed of dna specifically designed to carry the task of controlling the genetic traits of our cells. Dna is constructed as a very large molecule made by linking a series of repeating units called nucleotides. A nucleotide is composed of a sugar, a phosphorous - containing group, and a nitrogen-containing molecule called a base. Four types of bases are associated with the dna structure: adenine (a), guanine (g),cytosine (c), thymine (t). The bases on each strand are properly aligned in a double-helix configuration, which is two strands of dna coiled together. As a result, adenine pairs with thymine and guanine pairs with cytosine. This concept is known as base pairing. The order of the bases is what distinguishes different dna strands.