BIOLOGY 1A03 Lecture 2: Theme 3 Module 3

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Rosa Da Silva

Document Summary

Identify how cells in multicellular organisms must differentiate their structure and function by regulating gene expression: examine how eukaryotic dna is organized into chromatin to maintain a transcriptionally inactive state, examine how genes are activated by remodeling chromatin. Dna compaction regulates gene expression: dna duplex 2nm in diameter, nucleosome fiber 10nm in diameter, chromatin fiber 30nm in diameter, coiled chromatin fiber 300nm in diameter, coiled coil 700nm in diameter, metaphase chromatid 1400nm in diameter. Nucleosome remodeling and accessing dna: within eukaryotic dna, we find that dna is tightly wound around a complex of histone proteins, forming the nucleosome structure, each nucleosome contains an octamer of 8 histone proteins around which. Cis-acting sequences are bound by proteins: general transcription factors bind to the promoter, and transcriptional activator proteins bind to enhancers. Eukaryotic transcription: through looping of dna, transcriptional activator proteins, mediator complex, rna pol ii and general transcription factors are brought into close proximity, allowing transcription to proceed.