3. (DNA)Deoxyribonucleic acid (DNA) Nucleic Acid – nucleotidePolymer  monomer = nucleotide.. –2 kinds of nucleic acids: DNA and RNA.

4. genes Coding sections in DNA are called genes. Genes code for protein production; (the hereditary info. in DNA tells cells how to make proteins)

5. Nucleotide: three components (CP: 230) (H: 197) – 5 C sugar (deoxyribose) – phosphate group –nitrogenous base (4 kinds in DNA) ThymineThymine AdenineAdenine GuanineGuanine CytosineCytosine

6. Nucleotide: three components (CP: 230) (Hon: 197) – 5 C sugar – phosphate group –nitrogenous base (4 kinds in DNA)

7. Four Kinds of Nitrogenous Bases Adenine binds to ThymineAdenine binds to Thymine Cytosine binds to GuanineCytosine binds to Guanine A-T and C-G (always)A-T and C-G (always) C C C C N N O O Thymine C C C C C N N O N Cytosine C C C C N N N Adenine N N C C C C C N N O N Guanine N N C

8. DNA STRUCTURE Shape is like twisted ladder. Called a double helix -two twisted strandsdouble helix –Bases =rungs of a ladder hydrogen bonds hold pairs together; A-T, C-G –Sugars - phosphates form sides of ladder. Covalent bonds in backbone

9. Carbons in the sugar are labeled 1’ (one prime) to 5’.

10. Model parts: 12 – White Tees [Deoxyribose] 6 – White connectors [Hydrogen bond] 12 – Black [Phosphate group] 3 – Green [Guanine] 3 – Blue [Adenine] 3 – Red [Thymine] Yellow3 – Yellow [Cytosine]

11. DNA Animation http://www.johnkyrk.com/DNAanatomy.html

12. Packaging DNA Fundamental unit is Nucleosome – DNA wound around proteins called histones. (Hon. page 151) Occurs at Prophase

13. Nucleosome

14. Nucleosomes Lowest DNA packaging level thread wound around a spool

15. DNA - By The Numbers! Each cell has about 2 meters (6 ft) of DNA. The average human has 60-75 trillion cells. Avg human has enough DNA to go from the Earth to the sun more than 400 times. DNA has a diameter of only 0.0000000002 meters (20Ǻ) [1Ǻ =10 -10 m] The earth is 150 billion meters or 93 million miles from the sun.

16. Karyotypes Normal human male karyotype (the total set of chrom. of an organism)

17. Karyotypes Normal human female karyotype

18. The History of DNA Gregor Mendel-1866 –Determined “Unit characters” were the method of passing on traits for inheritance Friedrich Meischer - 1868 –Studied nuclei of pus cells obtained from discarded surgical bandages –Detected a phosphorus-containing substance that he named nuclein.

19. Frederick Griffith 1928 : Work with Bacteria –Found that DNA taken from a virulent (disease-causing) strain of bacteria (Streptococcus pneumoniae) –Transformed a non-virulent form of the bacterium into a virulent form.

20. Oswald Avery, Colin MacLeod, and Maclyn McCarty 1943 Continued the study of “Transformation” principle

21. Mendel Meischer Griffith Avery McCartyMacLeod

22. Transformation Of Bacteria Two Strains Of Streptococcus Smooth Strain w/Capsule (Virulent) Rough Strain (Harmless) Capsule

23. Experimental Transformation Of Bacteria -Griffith’s Experiment Control OUCH! Rough Smooth (virulent)

24. The History of DNA Alfred Hershey and Martha Chase - 1952 –radioactive isotope tracer experiment –bacterial virus (bacteriophage T2) infects a host cell ( bacterium Escherichia coli) –found that T2 virus DNA, not its protein coat, enters the host cell –genetic information for replication of the virus

25. Using S 35 Bacteria grown in normal non- radioactive media T 2 grown in media containing S 35 incorporate S 35 into their proteins Blending causes phage protein coat to fall off T2 attach to bacteria and inject genetic material Is protein the genetic material? When centrifuged, phage protein coats remain in the supernatant while bacteria form a pellet. The supernatant is radioactive, but the pellet is not. Did protein enter the bacteria?

26. Using P 32 Bacteria grown in normal non- radioactive media T2 grown in P 32 containing media incorporate P 32 into their DNA Blending causes phage protein coat to fall off T2 attach to bacteria and inject genetic material Is DNA the genetic material? When centrifuged, phage protein coats remain in the supernatant while bacteria form a pellet The pellet is radioactive, but the supernatant is not. Did DNA enter the bacteria?

27. The History of DNA Structure Erwin Chargaff- 1940 - “Chargaff’s rule” – four bases may occur in varying proportions in DNA of different organisms –# of A = # of T, w/ two hydrogen bonds – = # of G and C are present w/ 3 hydrogen bonds Rosalind Franklin and Maurice Wilkins –X-ray diffraction study concluded DNA fibers have two strands.

28. The History of DNA Structure James Watson and Francis Crick - University of Cambridge -1953 Worked on problem of making a DNA molecule model that was double stranded but also had the specific A - T and G - C base equivalencies Solution-double helical structure for DNA.

29. Chargaff Franklin Wilkins

30. Watson and Crick