1. 5-1 Notes: Structure of DNA
Chapter 10

2. Structure of DNA DNA is Made up repeating units of nucleotides
Three parts of a Nucleotide are:
Deoxyribose sugar
Phosphate group
Base

3. DNA Bases
Purines (two ringed)
Adenine and Guanine

4. DNA Bases Purines (two ringed) Adenine and Guanine
Pyrimidines (one ringed)
Thymine and Cytosine

5. Base Pairing Rules Adenine pairs with Thymine
Guanine pairs with Cytosine
Chargaff’s Rule: The % of “A” always equals the % of “T”, and the % of “G” equals “C”.

6. DNA Bonds Hydrogen bonds hold bases together
Covalent bonds hold backbone together
The backbone (sides) of the strands are alternating phosphate and deoxyribose sugars

7. The Double Helix Double Helix: Phrase used to describe shape of DNA
Double stranded, coiled like a spiral stair