BIOLOGY 1A03 Lecture 11: Theme 3 Module 3
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BIOLOGY 1A03 Full Course Notes
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All embryonic stem cells are identical at one point and differentiate into ~200 different: cells will have different fates based on the signals that are exchanged and which genes are switched on or off at specific times. The variation in cell types depend on the differentiation that occurred from common stem cells during the early developmental cascade: transcription factors. Proteins containing structures that allow them to interact with the dna double helix, control transcription and contribute to gene regulation. Important for determining the pathway for a specific cell type and what it differentiates into. Transcriptional regulation in prokaryotes and eukaryotes are similar: proteins that can activate/repress transcription, rna polymerase binds to promoters. Transcriptional regulation in eukaryotes: rather than having operons that cluster together genes with similar functions, every gene in eukaryotes has its own promoter and enhancer, dna is organized into highly compact chromatin. Genes within this tightly wound heterochromatin are usually expressed.