1. DNA
Chapter 12

3. 2.What is the relationship between genes and DNA (12-1)?
Our genes are made of DNA that store, copy, and transmit information from parent to offspring

4. 3. Structure of DNA 12-2
DNA= deoxyribonucleic acid, long strands of nucleotide bases joined by hydrogen bonds
Remember nucleic acids made of nucleotides
nucleotides are made of a 5 carbon sugar (deoxyribose), phosphate group, and nitrogenous base
4 types of nitrogenous bases: adenine, thymine, guanine, and cytosine

5. Structure cont'd...
Double Helix-like a twisted ladder following base pairing where Adenine pairs with Thymine and Guanine pairs with Cytosine
Chargraff's Rule- % of bases occur in equal amounts
2 strands run in opposite directions

6. Those involved with the discovery of DNA Structure
Early 1950s, Sister Miriam Michael Stimson, chemist that affirmed the structure of DNA bases and the double helix

7. DNA discovery continued...
Franklin, 1952, used X-ray diffraction & produced an X-ray image of DNA, revealing the helix structure

8. In1953
Watson & Crick "publish" the model of DNA as a double helix

9. 4. DNA Replication 12-3
Copying of DNA for new cells occurs in interphase
DNA can be copied because each base on one strand pairs with only one base on the opposite strand. Therefore each half of DNA has the exact information to make exact copies!

10. The process of DNA replication
1st the DNA is split in 2 strands creating replication forks at the top & bottom
DNA polymerase adds complimentary bases to each strand following the base pairing rule
Each New DNA molecule has 1 new & 1 old strand

11. 5. How DNA is part of a chromosome?

12. DNA is wrapped around histone a that create bundles t nucleosomes which coil. Those coils create super coils that make up chromosomes