unit 3 lect 18 - a gene encodes an enzyme (296-298)...

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Lecture 18 Biol 002 3-02-07 Reading: Chapter 14: 288-298 Chapter 15: 304-305 Note the terms below and look for them in your reading I. Meselson-Stahl: DNA replication is "semiconservative" (pages 288-289) look at Fig. 14.12 tube 3 shows the meaning of "semiconservative" at the end of replication, one strand is new, the other is old How did isotope-labelling with heavy and light N allow them to match DNAs in their experimental results with DNAs predicted by hypothesis? II. Read about DNA synthesis (pages 290-295) including the meaning of each term and its role in the process origin of replication replication fork polymerase only works in 5' to 3' direction - why? Template-old strand that is copied primer-RNA primase-enzyme that starts replication leading strand- lagging strand- Okazaki fragment- Ligase- helicase-unwinds double helix in bacteria III. Beadle-Tatum idea of a gene:
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Unformatted text preview: a gene encodes an enzyme (296-298) "one gene - one enzyme" note particularly Fig. 14.21 later work showed that proteins have specific sequences of amino acids (p. 298) At about the same time, genes were shown to be somehow made of DNA Chemists had long ago shown that DNA was a string of nucleotides covalently connected If one gene led to one protein, what hypothesis was proposed for the question: How does a gene structure specify a protein structure? IV. The connection: the genetic code (304-305) But the connection involved a third molecule: RNA (and that will be where lecture 19 begins . ..) Question about DNA structure and chromosome structure: In a tetrad of prophase I, how many strands of DNA are there? (each "strand of DNA" is a separate covalently linked molecule of DNA)...
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This note was uploaded on 04/07/2008 for the course PRE MED 101 taught by Professor Bio2,chem24,bio100 during the Winter '08 term at Marquette.

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