BIOLOGY 1A03 Lecture Notes - Lecture 13: Embryonic Stem Cell, Dna Binding Site, Chromatin
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BIOLOGY 1A03 Full Course Notes
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All embryonic stem cells are idenical at one point and difereniate into ~200 diferent types: cells will have diferent fates based on the signals that are exchanged and which genes are switched on or of at speciic imes. The variaion in cell types depend on the difereniaion that occurred from common stem cells during the early developmental cascade: transcripion factors. Proteins containing structures that allow them to interact with the dna double helix, control transcripion and contribute to gene regulaion. Important for determining the pathway for a speciic cell type and what it difereniates into. Transcripional regulaion in prokaryotes and eukaryotes are similar: proteins that can acivate/repress transcripion, rna polymerase binds to promoters. Transcripional regulaion in eukaryotes: rather than having operons that cluster together genes with similar funcions, every gene in eukaryotes has its own promoter and enhancer, dna is organized into highly compact chromain. Genes within this ightly wound heterochromain are usually expressed.