Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

DNA discovery & Structure 8.1 & 8.2

2,396 views

Published on

Published in: Education, Technology
  • Be the first to comment

DNA discovery & Structure 8.1 & 8.2

  1. 1. DNA TIMELINE
  2. 2. What is DNA? DNA stands for Deoxyribo Nucleic Acid. DNA carries all of the genetic information for an organism.
  3. 3. 1910: Thomas Morgan, through experiments with fruit flies, confirms that chromosomes are the molecules of inheritance.
  4. 4. 1928: Frederick Griffith conducts the first genetic experiments on mammals. His experiments dealt with mice and the pneumonia virus. He used two forms: the S form (deadly) and the R form (not deadly). A transforming material passed from dead S bacteria to live R bacteria, making them deadly.
  5. 5. 1944: Oswald Avery becomes the first scientist to suggest that DNA was the molecule of inheritance. Before Avery, biologists believed inheritance was controlled by proteins.
  6. 6. 1950: Edwin Chargaff determines that certain purines and pyrimidines occur in equal amounts in a DNA strand. This leads to Chargaff’s Rules: the amount of A = the amount of T, and the amount of G = the amount of C. “For every A there is a T, for every G there is a C”
  7. 7. 1952: Rosalind Franklin photographs a DNA molecule using an X-ray camera. Her photograph provides evidence that DNA is made of more than a single strand of nucleotides.
  8. 8. Franklin’s co-worker, Maurice Wilkins, gives the photograph to a pair of scientists, James Watson & Francis Crick , who are trying to determine the structure of DNA.
  9. 9. 1953: Using Franklin’s photo and Chargaff’s Rules, Watson & Crick develop a model of DNA. The model consists of two strands of nucleotides bonded together in the shape of a twisted ladder. This shape is known as the double helix.
  10. 10. DNA Structure is the same in all organisms. DNA is a Nucleic Acid (one of the macromolecules [polymers] we learned about during our Biochemistry unit) made up of long chains of nucleotides. Each nucleotide has three parts. phosphate group deoxyribose (sugar) nitrogen-containing base
  11. 11. DNA Structure  DNA consists of two strands of nucleotides. DNA looks like a twisted ladder The “backbone” of the ladder is formed by bonds between the...  Sugars (Deoxyribose)  Phosphates. The “rungs” of the ladder are formed by hydrogen bonds between nitrogenous bases. Nucleotide Sugarphosphate backbone Hydrogen bonds
  12. 12. 1. Purines: larger bases. There are two purines. A. Adenine (A) B. Guanine (G) 2. Pyrimidines: smaller bases. There are two pyrimidines. A. Cytosine (C) B. Thymine (T) A G C Phosphate T Deoxyribose
  13. 13. DNA Structure Each base pair consists of one purine and one pyrimidine. Pairs are bonded by HYDROGEN BONDS Following Chargaff’s Rules , for every Adenine (A) there will be a Thymine (T), and for every Guanine (G) there will be a Cytosine (C). Label your diagram to match this! Nucleotide Sugarphosphate backbone Hydrogen bonds

×