Unit 2 LE4 The Language of Heredity The history of DNA

1. Who was the first to study inheritance of traits? Gregor Mendel 1866

Large amount found in cells Numerous functions within cell Made up of 20 amino acids with almost an infinite number of combinations Allow for the diversity of traits seen 2. Why did some scientists believe protein was the molecule that stored information?

What does this picture represent? Nucleotide Label the 3 parts 3. Nitrogenous base What does this picture represent? Nucleotide Label the 3 parts Phosphate Sugar: Deoxyribose

4. What did Oswald Avery show in 1943 That DNA directs the expression of traits within an organism and transfers from one generation to the next

That DNA is the molecule that transfers information for traits 5. What question did Hershey and Chase answer in their experiment in 1952? That DNA is the molecule that transfers information for traits Was it DNA or proteins that express traits?

6. What was the bacteriophage experiment that proved DNA is genetic material?

Chargaff’s Rule What does the table tell you about the DNA in all organisms? What about the proportions in humans? All organisms contain the 4 bases: adenine, thymine, guanine and cytosine Equal proportions of A&T and C&G 30 + 30 = 60% 20 + 20 = 40% 100%

What are the facts about the structure of DNA? Made up of 6 parts Phosphorus Sugar 4 nitrogenous bases Double helix 2 strands Opposite directions Form complimentary pairs Hydrogen bonds between bases What are the facts about the structure of DNA?

Timeline: Mendel, Johannsen, Bateson, Griffith, Avery, Hershey & Chase, Chargaff, Franklin, Watson & Crick Mendel 1866