1. DNA: structure and function

2. DNA Deoxyribonucleic acid 1. Nuclear DNA – In nucleus of cell + proteins, form a chromosome – A set of DNA molecules is called a genome. 2. Mitochondrial DNA – In mitochondria Cytoplasmic organelle – Inherited from mother only

3. DNA structure Double helix Basic building block is the nucleotide – phosphate group + deoxyribose + base Purines: adenine, guanine Pyrimidines: thymine, cytosine Complementary base pairs: A-T; G-C

4. DNA function 1. replication Long, thin molecules All the DNA in a human individual: c. 200 times the distance from the Earth to the sun.

5. Figure 3.10 The Steps of DNA Replication Our Origins, 2nd Edition Copyright © 2011 W.W. Norton & Company

6. Figure 3.14a The Steps of Mitosis in Humans Our Origins, 2nd Edition Copyright © 2011 W.W. Norton & Company

7. Figure 3.15 Meiosis Our Origins, 2nd Edition Copyright © 2011 W.W. Norton & Company