BIOL-L 211 Lecture 5 Outline of Last Lecture I. BacteriaII. BacteriophageIII. DNAOutline of Current Lecture I. DNA ComponentsII. DNA Genetic SequenceIII. TransposonsIV. PseudogenesCurrent LectureDNAI. DNA ComponentsA. Chromatin: complex of DNA & proteinB. Histones: Proteins that compact eukaryotic chromosomes (not present in prokaryotes)C. Nucleosome: unit of DNA wrapped around histonesD. Diploid (somatic cell- 2 complete sets of chromosomes) or Haploid (gamete- one set of unpaired chromosomes)E. Gene Density (correlates to the amount of Junk DNA [DNA that doesn't code for anything])- more complex organisms tend to have smaller gene density; more "junk DNA" separates genesII. DNA Genetic SequenceA. Introns: Non-protein coding regions within genes (note: introns ~ interruptions)B. Exons: Coding regions of DNAC. Intergenic Regions: non-coding DNA between genes (NOT INTRONS)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.D. Repetitive Sequences1. Microsatellites: (micro -> short) dinucleotide repeats; copying errors2. Genome-wide Repeats: (relatively large, as suggested by "genome-wide") can be close together or dispersed, can also be transposons (which leads to the next point)III. Transposons (jumping genes- as opposed to jumping beans ;) )A. Characteristics1. Have personal gene encoding the transposase enzymea. Transposase enzyme: cuts out and relocates transposonsb. May cause mutation//duplication2. Inverted terminal repeats (recognized by transposase)B. Composite Transposons1. Additional gene between insertion sequences2. Often found in bacteria3. Can allow antibiotic resistanceC. Cut and Paste Transposition1. Exactly what it sounds like2. Transposase removes transposon from one site and inserts it into a new, target site3. The DNA at the target site is split apart (at the phosphodiester bonds), leaving two "sticky ends" (because DNA is double stranded and both strands split apart)a. Sticky ends are the genetic sequences at the target site4.When the transposon attaches, DNA polymerase & ligase have to fill in the gaps created5. IMPORTANT RESULT: Target site duplicationIV. PseudogenesA. Reverse transcriptase: facilitates reverse transcription [process utilized by some viruses], using RNA as a template to produce DNAB. Result has no introns, because it comes from RNA (which has already spliced out the introns)C. Articles For this class: "The Gene Hunt: Should Finders Be Keepers?" – Scientific American, July 29, 2009 and "U.S. Supreme Court Strikes Down Human Gene Patents" –June 13, 20131. The main idea here is that the Supreme Court decided that while DNA could not be patented, cDNA could as it did not occur naturally- but this lecture proves that to be FALSE as viruses already do
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