1. INTRODUCTION TO DNA By the end of this lecture you will know:
The basic function of DNA
The basic structure of DNA
Who discovered the structure of DNA

2. What is DNA Deoxyribonucleic acid
Master copy of hereditary information
DNA controls all of the activities of the cell
Every cell contains a complete copy of DNA
Prokaryotic cells-DNA is in the cytoplasm
Eukaryotic cells-DNA is contained In nucleus

3. Function: DNA must Carry information from one generation to the next.
Put that information to work.
Be easily copied.
Griffith. Transformation of bacteria
1944- Avery. Repeated Griffith's experiment. Repeated it after destroying DNA- no transformation

4. DNA is Simple DNA is just a string of nucleotides
A sugar and a nitrogenous base- just 3 parts
’s leading scientists thought DNA just a bunch of simple nucleotides

5. 4 different bases 4 different nucleotides
Adenine
Thymine
Cytosine
Guanine

8. Search for the structure
By the 1950’s everybody was looking for structure of DNA

9. Watson and Crick Discover the Structure of DNA
1952 Rosalyn Franklins xray pictures- suggests 2 strands
Watson is 23 at the time- they both win the nobel prize in the early 60’s

10. DNA – The Double Helix Model
DNA twisted double helix “ladder”
Rails sugar-phosphate backbone
“Rungs” are nitrogenous bases

11. 4 Bases Always Pair the Same Way
Adenine-Thymine
Cytosine-Guanine

12. nucleotide: one sugar, one phosphate, one base.
REVIEW
nucleotide: one sugar, one phosphate, one base.
4 bases
Adenine
Guanine
Cytosine
Thymine
Go back to first slide and review

13. Q Card Quiz What is……….. The basic function of DNA
The basic structure of DNA
Name the four nitrogenous bases
Match the bases correctly