BIOL 260 Chapter Notes - Chapter 4.1: Friedrich Miescher, Nitrogenous Base, Adenine
Document Summary
Dna structure and function: composed of sugar, phosphate groups, and nitrogenous bases, humans have 46 chromosomes, dnas are polymers of nucleotides, nucleotides consists of a sugar, a phosphate group, and a single-or double- ringed nitrogenous base; Pyrimidines (single carbon-nitrogen ring): cytosine and thymine. Purines (double carbon-nitrogen ring): adenine and guanine. Adenine and thymine pairs together and adenine and guanine pairs together: dna is like a stair case: The sidepieces are composed of phosphate groups and deoxyribose (a sugar) The bases hold the backbone together with hydrogen bonds: function: to carry instructions, called genes, for the synthesis of proteins. Each chromosome is packed into its own spheroidal region of the nucleus, called a chromosome territory. These can change from movement to movement and are not static: during prophase, each chromosome consists of two parallel filaments called sister chromatids and become thicker but shorter than their normal structure. The midpoint that pinches the two sister chromatids together is called.
