2. DNA Replication The process of copying DNA before cell division This occurs before BOTH mitosis & meiosis

3. Replication of DNA DNA Replication

4. Meiosis versus Mitosis Mitosis is essential for cell growth –Each daughter cell is genetically identical to the parent cell. –It’s simply a way to make more of the same cell Meiosis is essential for sexual reproduction –Each daughter cell is unique –The chromosome number is cut in half –Makes sex cells which will combine traits with another individual

5. Reproduction Sexual reproduction –2 parents contribute to create genetically unique offspring Pros and Cons –Require another individual –Creates genetic variation

6. Genetic variation Why is variation good? –A genetically similar population can be more easily attacked by diseases –The population survival won’t be all or nothing –Cope with new conditions, adapt to new environments

7. Replication of DNA Click this image to view movie

8. Homologous chromosomes versus chromatids Homologous chromosomes One from Mom and One from Dad Have different versions of the same genes Sister chromatids Bound at center by centromere Chromatids are identical Product of DNA replication

9. Copying DNA Original DNA Original DNA Strand Free Nucleotides New DNA molecule New DNA Strand New DNA molecule