1. DNA Mr. Skirbst Life Science Topic 07

2. DNA Deoxyribonucleic acid

3. DNA Deoxyribonucleic acid - stores & passes on genetic info from one generation to the next

4. Structure of DNA Watson & Crick 1962 developed model of DNA

5. Structure of DNA Watson & Crick 1962 developed model of DNA - “twisted ladder” (double helix)

6. Structure of DNA Watson & Crick 1962 developed model of DNA - “twisted ladder” (double helix) - “steps” made from 4 nitrogen bases

7. Double Helix Structure

8. Nitrogen Bases of DNA A – adenine

9. Nitrogen Bases of DNA A – adenine T – thymine

10. Nitrogen Bases of DNA A – adenine T – thymine G – guanine

11. Nitrogen Bases of DNA A – adenine T – thymine G – guanine C – cytosine

12. Nitrogen Bases of DNA A – adenine T – thymine G – guanine C – cytosine

13. Nitrogen Bases of DNA

14. Replication of DNA

15. Duplication of DNA 1. DNA “unzips”

16. Replication of DNA Duplication of DNA 1.DNA “unzips” 2.“free” N bases pair up

17. Replication of DNA Duplication of DNA 1.DNA “unzips” 2.“free” N bases pair up 3.2 new DNA molecules form

18. Chromosomes & DNA Chromosomes

19. Chromosomes & DNA Chromosomes - rod-shaped structures in nucleus where genes are found

20. Chromosomes & DNA Chromosome Theory

21. Chromosomes & DNA Chromosome Theory - genes are carried from parent to offspring on chromosomes (ex. Humans have 23 pairs Fruit flies have 4 pairs)

22. Chromosomes & DNA Meiosis - production of SEX CELLS with ½ normal # of chromosomes (through two divisions)

23. Meiosis male

24. Meiosis female 1 egg 3 Polar Bodies (disintegrate)

25. Goober Chromosomes (4 pairs) 4 legs 2 eyes 1 tail fur

27. Goober What would happen if all chromosomes from both parents were combined? What would happen if some of the chromosomes were missing?

28. Meiosis Why is meiosis needed?