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A lion hunter… In The Jungle Dark… And A Chinese Dentist… And A British Queen… All Fit Together.

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Presentation on theme: "A lion hunter… In The Jungle Dark… And A Chinese Dentist… And A British Queen… All Fit Together."— Presentation transcript:




4 A lion hunter… In The Jungle Dark… And A Chinese Dentist… And A British Queen… All Fit Together

5 The 53 rd Calypso Of Bokanon A lion hunter In the Jungle Dark And A Chinese Dentist And A British Queen All Fit Together The Central Dogma of Bokanon

6 What is Dogma?

7 DOGMA DEF: An unshakeable, commonly held belief In biology, the CENTRAL DOGMA states that all life demonstrates continuity within change over time We all “fit together”

8 How do we “all fit together” biologically?

9 The Central Dogma All life shares a common language for the synthesis of protein The “language” is the nucleic acid 5’-Deoxyribonucleic Acid or “DNA”


11 What Makes A Language Efficient and Effective?

12 Characteristics of Effective Languages 1) Universal/Able to be used by large numbers of individuals 2) Efficiency in communicating critical information 3) Ability to be obtained and used by successive generations 4) Ability to prevent changes that would diminish the accurate passage of information 5) Ability to repair or correct changes that do occur

13 How does Deoxyribonucleic Acid exhibit these characteristics?

14 Friedrich Miescher Obtained “acid-fast” dye from World Exposition of 1865 In 1869, Miescher extracted material from the nucleus of Leucocytes (white blood cells) and was able to stain them with the acid-fast dyes First identification of NUCLEIC ACIDS and CHROMOSOMES

15 What Is The Function of Nucleic Acids?

16 Griffith Experiment Fred Griffeth 1928 Streptococcus pneumoniae has two distinct forms –Unencapsulated –Encapsulated –The encapsulated form caused pneumonia but the unencapsulated strain does not cause pneumonia

17 Griffith’s Protocol When either live unencapsulated OR dead encapsulated bacteria were injected into mice, they survived When dead encapsulated bacteria were mixed with live encapsulated bacteria, then injected, the mice died of pneumonia Examination of the mice showed high levels of encapsulated bacteria

18 Significance of Griffith Experiment There is something inside of cells that determines their traits. This substance is merely a component or part of the cell When transferred to another cells, this substance can transform the traits of another organism

19 What do these results mean?

20 Avery’s Experiment Oswald T. Avery 1943 Transformed bacteria merely by exposing them to the chromatin (DNA & Protein) obtained from other, toxic bacteria

21 What do these results mean?

22 Significance of Avery’s Experiment The transformative substance inside of cells is the chromatin

23 Hershey & Chase Alfred Hershey & Martha Chase 1952 Infected bacteria with BACTERIOPHAGES (viruses) The protein capsule of bacteriophages contains sulfur but not phosphorus The nucleic acids of bacteriophages do not contain sulfur but do contain phosphorus

24 Hershey & Chase Results When bacteriophages infected bacteria, they left the sulfur outside of the bacterial host cells The phosphorus was passed into the host cells

25 What do these results mean?

26 Significance of Hershey & Chase Protein was not causing the changes in the host cells The transformative substance must be the nucleic acid, 5’-Deoxyribonucleic Acid

27 The Transforming Principle The information for the traits/features of an organism is contained in the nucleic acids If another organism receives these nucleic acids, it may express the same traits as the original

28 How does the structure of 5’-Deoxyribonucleic Acid Cause These Changes In Living Organisms?

29 Levine Experiment P.A. Levine (1920) Building upon Miescher’s identification of DNA as an acidic substance, Levine identified the constituant parts of Deoxyribonucleic Acid Three parts constitute a NUCLEOTIDE

30 NUCLEOTIDE MONOMERS Deoxyribose (pentose carbohydrate/sugar) Phosphoric Acid Nitrogenous Bases

31 Purines Adenine (A) Guanine (G) Adenine forms two hydrogen bonds Guanine forms three hydrogen bonds

32 Pyrimidines Cytosine (C) Thymine (T) Thymine forms two hydrogen bonds Cytosine forms three hydrogen bonds

33 Chargaff’s Ratios Erwin Chargaff Chemical analysis of nucleic acids obtained from several different species were compared regarding the relative proportions of the four nitrogenous bases

34 What Do These Results Mean? Source%A%G%C%T Human Liver 30.319.519.930.3 Human Thymus 30.919.919.829.4 Herring Sperm 27.822.222.627.5 Yeast31.718.217.432.6

35 Complimentary Base Pairing Due to their complimentary numbers of hydrogen bonds, only certain nitrogenous bases may pair Adenine-Thymine Cytosine-Guanine

36 Structure of A Nucleotide Nucleotides are made of three parts PO 4 attached to 5’ carbon of deoxyribose Nucleotides may be linked together as a polymer via dehydration synthesis -OH removed from 3’carbon of deoxyribose and H removed from PO 4 group

37 Look Familiar?

38 How does the form of DNA allow itself to be replicated?

39 Pauling’s Experiment Linus Pauling Showed that the form of proteins in the nucleus of living organisms were often twisted into a helix

40 X-Ray Crystallography Bombarding biomolecules with x- ray radiation and exposing the result to a photographic plate reveals the shadow of the biomolecule Using the shadow, the shape of the biomolecule may be deduced

41 Wilkins & Franklin Maurice Wilkins and Rosalind Franklin exposed DNA to X- ray bombardment and photographed the result Franklin’s photos of DNA indicated that it was a helix

42 Watson & Crick James Watson & Francis Crick (1953) Using data from Chargaff & Franklin, they determined that DNA must be a double (not single) helical polymer

43 Modeling DNA Through construction of a model, Watson & Crick determined that by using the complimentary base pairing of A-T & C-G, DNA could attain a double helix shape

44 The Significance of Watson & Crick Provided an explanation for how all the “parts” of DNA could be arranged in a manner that would allow the molecule to replicate itself 1 st Part of Central Dogma



47 During mitosis, the supercoils of DNA may be further condensed into chromosomes

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