1. DNA Notes

2. History of DNA
James Watson and Francis Crick are given most of the credit for discovering the structure of DNA
They used x-rays from Rosalind Franklin
determine the spiral shape

3. The Evidence and Models
Rosalind Franklin’s Watson and Crick’s
X-ray of DNA original model

4. What is DNA Made Of? The backbone of DNA is made of: Phosphate
Deoxyribose (sugar)
** These molecules alternate all the way down the side of the molecule

5. What’s in the middle? There are four base molecules
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
The bases form specific pairs
Adenine pairs with thymine (A-T) or (T-A)
Cytosine pairs with guanine (C-G) or (G-C)

6. Here is the full picture!

7. Nucleotides Nucleotides are the pieces that make up a strand of DNA
Each nucleotide is made of:
A sugar (deoxyribose)
A phosphate
A base

8. Replication DNA replication occurs when a copy of the DNA is made
Replication occurs during mitosis and meiosis
If all goes well, the copy is identical to the original strand of DNA

10. Mutations
A mutation is a mistake in the DNA that usually occurs during replication
Not all mutations are harmful
Types of mutations:
Insertion
Deletion
substitution

11. Insertion
Extra bases are added to the strand

12. Deletion
Bases are left out of the strand of DNA

13. Deletion
Entire sections of chromosomes can be deleted

14. Substitution Bases are replaced with different bases
Ex: sickle cell anemia

15. Substitution, con’t