Chapter 16 - Chapter 16: The Molecular Basis of Inheritance...

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Chapter 16: The Molecular Basis of Inheritance 16.1 DNA is the genetic material 1. Evidence that DNA can transform bacteria a. Frederick Griffith studied Streptococcus pneumoniae , a bacteria that causes pneumonia in mammals. He found: transformation which is a change in genotype and phenotype due to the assimilation of external DNA by a cell. He found this by killing pathogenic bacteria with heat and then mixing the cell remains with living bacteria of the nonpathogenic strain. Some of the living cells became pathogenic. b. Oswald Avery found that DNA was the transforming agent. 2. Evidence that Viral DNA can program cells a. Bacteriophages are viruses that infect bacteria. (also called phages ) b. Alfred Hershey and Martha Chase performed experiments showing that DNA is the genetic material of a phage known as T2. 3. Additional Evidence that DNA is the genetic material a. Erwin Chargaff analyzed the base composition of DNA from a number of different organisms, and found that the base composition varies from one species to another. b. He also found that the number of approximately thymines equaled the number of guanines, and the number of guanines equaled the number of cytosine. c. Rosalind Franklin concluded that the sugar-phosphate backbones were on the outside of the double helix. d. Each base had chemical side groups that can form hydrogen bonds with its appropriate partner: Adenine can form two hydrogen bonds with thymine; guanine forms three hydrogen bonds with cytosine. 16.2 Many proteins work together in DNA replication and repair 1. The basic principle : Base pairing to a template strand a. Semiconservative model can be distinguished from a conservative model of replication, in which the two parents strands somehow come back together
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This note was uploaded on 02/07/2012 for the course BIO 1711 taught by Professor Burleson during the Spring '11 term at North Texas.

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Chapter 16 - Chapter 16: The Molecular Basis of Inheritance...

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