1. Section 11.1 DNA: The Molecule of Heredity

2. Within the structure of DNA, is the complete instructions for manufacturing all the proteins for an organism.

3. Structure of DNA Polymer made of repeating subunits called nucleotides Nucleotides have 3 parts:  1. Simple sugar – Deoxyribose  2. Phosphate group  3. A nitrogen base (four possibilities)

4. Structure of DNA cont. Double helix – two strands twisted together  Deoxyribose and phosphate group form the sides of the ladder by covalent bonds  Nitrogen bases form the rungs of the ladder by hydrogen bonds.

5. Nitrogen Bases Purines: double rings  Adenine  Guanine Pyrimidines: single ring  Thymine  Cytosine

6. Base Pairings Adenine-Thymine Guanine-Cytosine A T T G A C T A A C T G