BIOL 120 1st edition Lecture 18 Outline of Last Lecture I Experiment method and Five Element model II Monohybrid crossing III Principle of Segregation IV Punnett Squares V Dihybrid crossing VI Human Blood Groups VII Environmental influence and other main ideas Outline of Current Lecture I Overview of Genetic Material II Review of DNA III DNA Replication Current Lecture I Over of Genetic Material A Frederick Griffith 1928 studied two strands of pneumonia causing bacteria 1 S strain caused pneumonia 2 R strain did not cause disease 3 infected mice with these strains a live S strain killed the mice and live R strain did not b heated S strand did not kill the mice virus was killed by heating 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 c combination of live R strain and heated S strain killed the mice Combination allowed DNA of heated S strain to recover in the live R strain a known as transformation II Review of DNA structure A It is a nucleic acid B Composed of 1 5 carbon sugar 2 phosphate group attached to 5 carbon 3 nitrogenous bases Adenine thymine cytosine guanine C Nucleotides attach at 3 with a phosphodiester bond form between the phosphate group of one nucleotide and the 3 OH of the next nucleotide D Strands grow in 5 to 3 direction E Chargaff s rule 1 equal proportions of Purines A and G and Pyrimidines C and T a amount of adenine amount of thymine b amount of cytosine amount of guanine F Rosalind Franklin 1 Discovered that DNA is helical 2 used Wilkins DNA fibers to determine that a molecule of DNA has a diameter of 2nm and a complete turn of the helix occurs every 3 4 nm G Watson and Crick 1 proposed a double helix structure for DNA 2 did not actual experiment just used other s research H DNA is a double helix 1 A forms 2 hydrogen bonds with T 2 G forms 3 hydrogen bonds with C III DNA Replication A occurs in Interphase B DNA copies are semiconservative part of the old strand bonded with new strand C Semiconservative theory proven by Meselson and Stahl 1958 1 grew cells in N15 and N14 2 DNA was extracted at different time intervals to view replication 3 N15 is heavier than N14 location of N15 DNA was lower than N14 DNA and the semiconservative strand of N14 and N15 was in the middle proving it true D Requires 1 Paternal DNA to copy and primer 2 Enzymes to copy DNA 3 NTPs building blocks to make copy of DNA E Process 1 Initiation 2 Elongation new strands of DNA are synthesized by DNA polymerase 3 Termination replication stops F DNA polymerase III 1 III is the only one used in DNA replication 2 matches existing DNA bases with complementary nucleotides 3 Features a adds new base to 3 end b synthesizes in 5 3 direction c requires a primer of RNA to function
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