BIO 1140 Lecture Notes - Lecture 4: Intron, Release Factor, Aminoacyl-Trna
23 Apr 2017
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Document Summary
Overview of dna structure: a double-stranded helix, twists towards the right, two strands running in opposite directions, antiparallel, 5" has a phosphate while 3" has oh. Dna packaging is necessary for chromosomes to be properly distributed during mitosis and meiosis. Eukaryotes wrap dna around a spool of protein, called histones. Nucleosomes: histone octomer: complex of 8 histone proteins, 2 each of 4 types, a 5th histone, h1, helps with combining the dna, nucleosomes are joined by linker dna , the nucleosomes can be held together either tightly or loosely. The interphase chromosome: heterochromatin: during interphase, portions of some chromosomes remain highly condensed. This chromatin is not transcribed: euchromatin: less compact chromatin. Replication in which each dna molecule is composed of one parent strand and one newly synthesized strand. If conservation, one daughter molecule will contain both parental. Dna strands, and the other will contains dna strands of all newly-synthesized material.
