07BIS1012013ReplicLect_7

233 5 3 dna dna replication replication a g t c a a c

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Unformatted text preview: and 11 in A-DNA. Z DNA appears longer and slimmerllooking than the B helix. ooking Unlike B-DNA and A-DNA, Z-DNA is Unlike dependent on the nucleotide sequence. Alternating G and C promotes the formation of Z-DNA. Therefore, stretches of Z-DNA can be found interspersed in Bof DNA chromosomes. DNA The presence of regions of Z DNA near The genes on the same molecule can influence their expression by promoting protein binding. protein BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez 26 Copying Mechanism (p. 233) 5’ 3’ DNA DNA Replication Replication A G T C A A C C G C A T C A A G G T T T G G T 3’ A T C G 5’ G G T T G G A T A C G A C C A T G A T T A C C A A T C 5’ 3’ BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez 3’ OH G C T C G 27 3’OH 3 Models for DNA Replications (p. 234) BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring2013—Genes and Gene Expression R.L. Rodriguez 28 Semiconservative Copying Mechanism (p. 234) BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez 29 Alternative Copy Mechanisms (p. 234) Conservative Dispersive BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez 30 Density (isopicnic) gradient ultracentrifugation ­ In 1957, Mat Meselson and Franklin Stahl used the heavy isotope of In nitrogen (N15) and ultracentrifugation to demonstrate that bacterial DNA nitrogen and replicates in a semiconservative fashion and not in a dispersive or conservative fashion. conservative N14 N15 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez 31 Meselson-Stahl Experiment (p. 234) ­ ­ ­ According to the According conservative model, “hybrid” density DNA is never produced. never While the dispersive While model would produce hybrid DNA at G1, it produces hybrid DNA at G2 and G3 as well. G2 Only the semiconservative model servative produces hybrid at G1 and light at G2. This is only consistent with the Watson and Crick structure for DNA. structure BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez 32 Chromosome Replication BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression R.L. Rodriguez 33 Replication of DNA (p. 236) ­ ­ ­ ­ With the exception of some viruses and bacteriophage, most With organisms, from bacteria to man, replicate their D...
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This note was uploaded on 02/12/2014 for the course BIS 101 taught by Professor Simonchan during the Spring '08 term at UC Davis.

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