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Gene Function and DNA Dynamics. Sept. 29, 2005. 2 (?) Epistatic loci. Structure of lac: What’s Missing?. What’s this?. “No Glucose” Env’t. What’s needed here?. “Environment”. 5 Controlled Loci (operons). Controlling protein from arg R operon. The Arginine Regulon. B, A, Z DNAs.
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Gene FunctionandDNA Dynamics Sept. 29, 2005
2 (?) Epistatic loci Structure of lac:What’s Missing? What’s this? “No Glucose” Env’t What’s needed here? “Environment”
5 Controlled Loci (operons) Controlling protein from arg R operon The Arginine Regulon
B, A, Z DNAs http://www.chem.umass.edu/~cmartin/Courses/BioStruct/DNA/DNA.html
Drawing of coiled and looped DNA in a Chromosome Chromosome Coiling
DNA is like Snoopy's Mtn. Cabin Sky light Smoke P P SUVport P 5' A T G C Plumb line (checks his foundation's stability) 4’ 1’ 2’ 3' -OH foundation
5’ 3’ 5’ 3’
DNA Polymerases up to30,000 bp/min, or 900 to 3,000 RPM “spin” Mutation lethal? Yes Yes Backspace Primer removal
? Initiation of DNA Replication ?
DNA Replication Initiation and Triple Stranded DNA In the human genome, DNA replication initiation regions have been found often to have triple-stranded DNA, and at fixed sites in the cell. These regions can be formed within a dimer (intramolecular) at regions with certain base compositions. These regions can be formed with a third polynucleotide of the appropriate base sequence in a particular region.
Intramolecular Triple Strands The foldbacked strand may be either 3’-5’ or 5’-3’ depending on the situation.
H-bonds in Triple Stranded DNA Pyrimidine Pyrimidine Purine
Eukaryotic RNA’sChap. 13 • MicroRNAs, RNAi, gene regulators genes (e.g. iRNA) • ribozymes • rRNA genes • tRNA genes • siRNA • primary transcript RNA (hnRNAs) • mRNA
Working Questions • In each of the diagrams shown, identify as many conditions that must be met before the activities shown could occur in a bacterium. • If the genes are part of a bacterium, what kind of substrate composition would be needed? (i.e. what basic requirements would be met from the culture medium) • Compare these conditions for a bacterium with those for a eukaryotic cell; what are examples of “special” requirements might be present, depending on the species? • What differences would be found if the eukaryotic cell was part of a differentiated tissue?