Danielle 9

Danielle 9 - Homework Required Problems: 26.1, 26.2, 26.3,...

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Homework Required Problems: 26.1, 26.2, 26.3, 26.4, 26.6, 26.11, 26.13, 26.14 (skip part b), 26.17, 26.19, 26.20, 26.21, 26.23, 26.29. 9.1--9.6, 9.8, 9.10--9.18, 9.22, 9.34 (the last question assumes that you remember the concept of molarity from chemistry!) (Plus my two problems in posted homework). Due March 26/28 Exam Tuesday April 1.
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Ch. 9 DNA (or RNA) is the genetic material. DNA structure. Prokaryotic chromosomes. Eukaryotic chromosomes. For anyone interested in the history of molecular biology: “The Eighth Day of Creation” H. Judson. Excellent and detailed. “The Double Helix” J. Watson. Fun, but biased. (Ya think?) = )
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Early 1900s: Nucleus found to contain lots of a large, acidic polymer rich in phosphate, nitrogen, and carbohydrate— The substance was DNA. But seemed less structurally complex than protein, and most believed protein was genetic material. Though accepted as fact today, it was not always obvious that DNA was the genetic material. It took a cohesive pattern of results from experiments performed over more than 50 years to convince the scientific community that DNA is the molecule of heredity. DNA as the genetic molecule
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Bacterial transformation implicates DNA as the substance of genes. In a study of Streptococcus pneumoniae bacteria grown in laboratory media, Frederick Griffith distinguished 2 types of bacterial forms: smooth (S) and round (R). S is the wild-type; a mutation in S gives rise to R. S forms appear smooth because they make a polysaccharide capsule that surrounds the cell. R forms, which arise spontaneously as mutants of S, can’t make the capsule and as a result, their colonies appear to have rough surface. Because the polysaccharide capsule helps protect the bacteria from host immune response, the S bacteria are virulent and kill most animals exposed to them; by contrast, the R forms fail to cause infection. In 1928, Griffith published the astonishing finding that genetic transformation from dead bacterial cells could somehow be transmitted to live cells.
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Continued…. In 1928, Griffith published the astonishing finding that genetic transformation from dead bacterial cells could somehow be transmitted to live cells. He was working with 2 kinds of bacteria: live R forms and heat-killed S forms. Neither produced infection when injected into mice, but a mixture of the 2 killed animals.
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This note was uploaded on 03/30/2008 for the course BIOL 2156 taught by Professor Larkin during the Spring '08 term at LSU.

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Danielle 9 - Homework Required Problems: 26.1, 26.2, 26.3,...

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