BIOL 2081C Lecture Notes - Lecture 16: Histone H3, Dna Supercoil, Dna Condensation
Document Summary
The condensed version of a chromosome is called a nucleoid and the. Dna is looped instead of like the regular structure of a eukaryote. Also the supercoiled and relaxed loops are independent of each other and relaxation of loop occurs from loop to loop. In eukaryotes the supercoiling happens near genes that are actively being transcribed. The dna structure when uncoiled is called chromatin because chromatin contains linear dna and histone proteins (h1, h2a, h2b, h3, and h4). Histone polypeptide chains carry about 20 to 30 percent arginine and lysine (positive). The positive charge of protein and negative of dna allow each other to bind to each other tightly due these opposite forces. Dna bound around histone is called nucleosome because it looks like a bead. Each unit includes 2 of each type of histone, 1 h1, and dna with 200 nucleotides.
