1. Bellwork Monday 12/5 * If you were absent last Friday, come in during tutorial to take test *Finals next Thursday and Friday 12/15 and 12/16 *We will do a big review packet that you can use on the final 1. What does DNA do? (If you have no clue, give it your best shot or ask your neighbors) Agenda: 1.Pass back tests 2.Whiteboards 3.Notes

2. Whiteboard reminders Please only write answers to the questions Please clean your whiteboard when you are finished Please throw away all paper towels

3. Whiteboards *No worries if you are unsure on these, give them your best shot! 1.What is the function of DNA in cells? 2.Where did your DNA come from? 3.Draw the structure of DNA, in as much detail as you can. 4.Why is DNA called a double helix? 5.What are 3 parts of a DNA molecule? 6.How do cells copy DNA *Bonus: What does DNA stand for?

4. DNA instructions for cells the Genetic Code passed to new cells & offspring

5. Dr. Watson! (And Dr. Crick)

6. DNA Structure 3 parts –D–Deoxyribose (a sugar) –P–Phosphate (a mineral) –N–Nitrogen-containing base

7. 4 types of bases –Adenine – A –Guanine – G –Cytosine – C –Thymine – T

8. DNA molecule shape is a double helix –Like a twisted ladder –Sides of Ladder Formed by sugar + phosphate “Sugar-phosphate backbone” –Rungs of Ladder Formed by pairs of bases

9. Base Pairs –A pairs only with T –G pairs only with C

10. Double helix can be split into two strands

11. 2 strands are Complementary –Like 2 halves of a dollar bill 2 strands are important –As a back up –Makes duplicating chromosomes easy

12. DNA facts The percent of your DNA you have in common with: Another person in this room- 99% A chimpanzee- 97% A dog- 75% A banana- 50% If you stretched all the DNA in all of you cells, it would reach the sun and back 4 times! The DNA in each cell contains roughly 3GB of storage

13. DNA Model (phase 1) Use templates of deoxyribose, phosphate and the 4 bases to make cut outs. Need: 6 deoxyribose 6 phosphates 6 bases that will make 3 pairs Alternate deoxyribose & phosphate for 2 backbones –Note that one backbone is upside down Pair bases in between for “rungs” –Note that one base must be turned upside down to match Glue them down.

14. DNA Replication 4 Steps 1) DNA molecule “unzips” –Double helix separates between base pairs

15. 2) each single strand acts as a template & is copied

16. 3) Result: –2 identical double strands –Both identical to original DNA –Each has 1 new & 1 original strand

17. 4) Errors are corrected –An enzyme slides along new strand –Compares it to original strand –Fixes any mismatches in new strand –Errors in mitosis can lead to cancer

18. Complementary base pairs Original DNA: C G G A T C A G T Complementary: _ _ _ _ _ _ _ _ _ A – T G - C

19. DNA Model (phase 2) Replication Unzip (cut) between the base pairs Get a second sheet of paper to add to middle Need: 6 more deoxyribose 6 more phosphates 6 more bases (like last time) Arrange 2 new sugar-phosphate backbones in center Add new complementary bases to each side Check for errors Glue them down