1. Objective: Discuss DNA and base pairing
12.1

2. Griffith’s experiment:
Injected disease causing bacteria into mice
They died
Injected harmless bac. Into mice
They lived
Injected heat-killed disease causing bac. Into mice
Injected harmless bac. And heat-killed disease causing bac. Into mice

3. Transformation-
when one strain of bacteria is changed into another strain
What caused it to change?
DNA

4. Avery:
Tried to see if bacteria would still undergo transformation if only DNA was present
Determined:
DNA stores and transmits genetic info.

5. Hershey-Chase experiment:
Further showed DNA is what stores/transmits genetic info (not protein)
Used radioactive markers for the protein in one experiment and radioactive markers for the DNA in the other experiment.

6. What is DNA made of?
Nucleotide- 5-carbon sugar, phosphate group and nitrogenous base
Nitrogenous base
Adenine, Guanine Cytosine, Thymine Purines Pyrimidines

7. Chargaff’s rule:
same number of Adenines (A) as Thymines (T)
same number of Guanine (G) and Cytosine (C)
Base pairing:
A pairs with T G pairs with C

8. Rosalind Franklin-
used X-rays to determine shape of DNA.
DNA had a cross shaped pattern
Watson and Crick-
used Franklin’s photos to come up with shape of DNA- double helix
Double helix- twister ladder