1. Nucleic Acid Structure and Function

2. Function of DNA (DeoxyriboNucleic Acid) Contains sections called “genes” that code for proteins. These genes are what are passed on from parent to offspring.

3. Structure of DNA Discovered by James Watson (US) and Francis Crick (UK) in 1954. Described the structure as a “double helix”

4. The Double Helix A twisted ladder

5. DNA is easier to view in its unwound shape: A ladder with split rungs

6. Nucleotides are the Building Blocks of Nucleic Acids There are 3 parts of the nucleotide: 5-Carbon (Pentose) Sugar Phosphate Nitrogen base

7. Nucleotide Structure

8. Sugar and Phosphate make the sides of the ladder

9. Nitrogen Bases make up the rungs of the ladder

10. Nitrogen Bases Broken down into 2 groups: Double Ring Bases Adenine Guanine Single Ring Bases Cytosine Thymine

11. Complementary Bases Complementary: Bases that pair to form a hydrogen bond A – T G – C Hydrogen bond

12. Molecular Structure Besides being twisted, the two strands of DNA run in opposite directions

13. A 3-Rung DNA molecule