Chapter 11  DNA STRUCTURE and FUNCTION

1. DOWNLOAD an Adobe Acrobat version of the chapter outline

2. Textbook website:
   1. outline, quiz, and flash cards: select from resources for chapter 11.
3. STARR AN TAGGART 10th edition website:
   1. outline, quiz, and flash cards: select from resources for chapter 13.
4. On-Line Biology Book by M. J. Farabee 
   1. DNA and Molecular Genetics
5. Kimball's Biology Pages
   1. The Hershey and Chase experiments
   2. DNA - The Double Helix from Kimball's Biology Pages
   3. Base Pairing
   4. The Meselson - Stahl Experiment
   5. DNA Replication from Kimball's Biology Pages
   6. DNA Repair
6. The Biology Project  an interactive online resource for learning biology, developed at The University of Arizona
   1. DNA Structure
   2. DNA Structure Activity
   3. Nucleic Acid Problem Set
7. MIT Biology Hypertext 
   1. The Search for Genetic Material
   2. Identification of DNA as the Genetic Material
   3. DNA replication
8. North Harris College Gene Regulation
9. Mendel Web
10. Build a DNA molecule from the Genetic Science Learning Center, University of Utah

DNA STRUCTURE and FUNCTION -- Chapter 11

Introduction 

1. Friedrich Miescher - 1871
2. chromosomes consist of protein and DNA [fig 13.1] and RNA 
3. Linus Pauling discovered the helical structure of proteins in 1951. 
4. Watson and Crick, 1953 [Figure 13.1]: Model of DNA [Fig. 13.2] 

13.1 – DISCOVERY OF DNA FUNCTION 

Early and Puzzling Clues 

1. Transformation of Bacteria (Fred Griffith, 1928) [fig 13.3] 
   1. S (pathogenic) and R (nonpathogenic) strains of a pneumonia-causing bacterium 
   2. Mice injected with live R cells plus heat-killed S cells all died
2. DNA not protein is the transforming substance (Oswald Avery, 1944)
3. Confirmation of DNA Function 
   1. Genetic Material of Viruses (Alfred Hershey & Margaret Chase, 1952) 
      1. bacteriophages [fig 13.4]
      2. labeled P of DNA, not labeled S of protein coat incorporated [fig. 13.5] into bacteria 

13.2 – STRUCTURE OF DNA 

Chemical Structure [fig. 13.6] 

1. nucleotide
   1.  = deoxyribose
   2. a phosphate
   3. nitrogenous base 
      1. purine (A or G)
      2. pyrimidine (T or C)} 
2. 3' C of one sugar is joined to the 5' phosphate of another [fig. 13-7] 
3. Chagaff's rules (1949): 
   • A = T; G = C
   • purines (A + G) = pyrimidines (T + C) 
4. X-Ray diffraction (Rosalind Franklin, Section 13.3) 

Watson and Crick Model 

1. double helix with sugar-phosphate backbone and paired bases
2. 5-carbon sugar deoxyribose
3. phosphate group joins nucleotides
4. complimentary base pairing
5. hydrogen bonds link complimentary strands [fig. 13.7] 
6. biological significance

13.4 – DNA REPLICATION AND REPAIR 

How is the DNA Molecule Duplicated 

1. Meselson and Stahl:  Replication is Semiconservative [fig. 13.9] 
   1. each new double helix contains one parental strand 
2. DNA helicase enzymes unwind helix during replication [Fig. 13.10]
3. DNA synthesis requires an RNA primer 
4. DNA polymerase: catalyzes polymerization of nucleotides
5. DNA replication is bidirectional
6. DNA synthesis is always in a 5' to 3' direction 
7. Synthesis of the leading strand is continuous; lagging strand is discontinuous 
8. DNA ligases connect sections of nucleotides 

Monitoring and Fixing the DNA

1. DNA polymerases, DNA ligases, and other enzymes proofread and repair the complimentary strands 
2. accuracy of Replication: average uncorrected error (mutation) 10^-8 to 10^-12; uncorrected errors can lead to cancer 

13.5 – DOLLIES, DAISIES, AND DNA

KEY TERMS FOR CHAPTER 11

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