Week 2: DNA Structure and Chromatin

University:
The Pennsylvania State University
Course:
BIOL 230W | Cellular Biology
Academic year:

2023
Views:

240

Pages:

1
Author:

Sarah Landeck

BIOL 230W - Week 2 Wednesday, January 18th — DNA Structure and Chromatin — DNA is antiparallel, meaning strands go in opposite directions, held together by Hydrogen bonds — In prokaryotes, there's no nucleus, transcription/translation are simultaneous — The purines are adenine and guanine, the pyrimidines are cytosine, thymine (DNA only), and uracil (RNA only) — attach to pentose (ribose or deoxyribose) — *draw A, C, T, G, U — Hydrogen bonds are less stable than covalent bonds, easier to split — C and G have 3 H-bonds, A and T have 2 H-bonds holding them together — The bond that holds 2 nucleotides together is a phosphodiester bond — The rst nucleotide is the 5’ end, the last nucleotide is the 3’ end — Ligases repair breaks in DNA backbone during replication Friday, January 20th — DNA Structure and Chromatin pt 2 — Breaking a phosphodiester bond cuts the strand in half horizontally — Genes are the protein-coding regions on a chromosome — Nucleosome: 1 set of 8 histones and the DNA that wraps around it fi — Heterochromatin is more tightly packed than euchromatin (active transcribe)