History of DNA Biology Mrs. Harper 2/7/18

November 30, 2015 Download notes Begin working on Do Now

Do Now 2/7/18 What is one interesting thing you did over Thanksgiving Break? What does DNA stand for? Which macromolecule is DNA an example of? Amino acids make up which macromolecule? Which organelle holds our DNA? What is the monomer of DNA?

DNA: Deoxyribose Nucleic Acid The Genetic Material Introduction to DNA

DNA What does DNA stand for? What is the function of DNA? Deoxyribo- nucleic acid type of nucleic acid RNA is other type What is the function of DNA? To store genetic material Where is DNA found? DNA is found in nucleus of eukaryotic cells

The History of DNA From 1866-1953

Searching for Genetic Material Gregor Mendel (1866): Discovered heritable traits (genes) Freidrich Miescher (1868): Isolated something new from the nuclei of eukaryotic cells (DNA)

Searching for Genetic Material Thomas Hunt Morgan (1910): Discovered genes are located on chromosomes

Searching for Genetic Material Fredrick Griffith (1928): Studied effects of virulent (virus-causing) bacteria vs. nonvirulent bacteria injected into mice believed that the transforming agent was an inheritance molecule.

Non-virulent vs. Virulent Bacteria ROUGH: harmless SMOOTH: kill

NOT HARMFUL/BENIGN BAD/HARMFUL

Searching for Genetic Material http://brookings.k12.sd.us/biology/ch12DNARNA/Chapter%2012A.mpg

Searching for Genetic Material Avery, MacLeod, & McCarty (1944): Reported that “transforming agent” in Griffith's experiment was DNA. Used bacteria (NOT mice)

Discovering the Structure of DNA Edwin Chargaff (1950) Discovered a 1:1 ratio of adenine (A) to thymine (T) and guanine (G) to cytosine (C) in DNA samples Chargaff’s Rules A = T C = G

Searching for Genetic Material Alfred Hershey & Martha Chase (1952) Confirmed DNA (not protein) molecule of heredity Used bacteriophages (viruses)

Searching for Genetic Material Hershey and Chase Experiment

Discovering the structure of DNA Photo 51 Rosalind Franklin (1952) Obtained sharp X-ray diffraction photographs of DNA (Photo 51)

 X-rays passing through a helix diffract at angles perpendicular to helix making an "X" pattern, which favors an equal diameter "helix".

Discovering the structure of DNA James Watson & Francis Crick (1953) Discovered double helix structure Solved the three-dimensional structure of the DNA molecule Watson Constructing Bair Pairs movie http://www.hhmi.org/biointeractive/dna/animations.html

DNA Structure Made up of nucleotides Phosphate group Five carbon sugar Nitrogen base

Assignment Complete the assignment independently on Code Red For the timeline be sure to include the year, the scientist and a description of the discovery Example: Gregor Mendel -Discovered heritable traits (genes) 1866