1. Take out your homework

2. DNA WHY does G pair with C? What forces hold the base pairs together? What are the three functions of DNA? What does ‘antiparallel’ mean?

3. Sugar - deoxyribose

5. 3’ 5’ 3’ 5’ 3’ to 5’ 5’ 3’ 5’ 3’ to 5’

6. The two strands are ‘antiparallel’ That’s how the charges line up

7. Adenine Guanine Cytosine Thymine

8. Guanine Cytosine

10. DNA What are the three functions DNA must perform? Store, Copy, Transmit So, how is DNA copied?

11. DNA A little background: -ase means enzyme enzymes are proteins that control reactions What’s a “polymer”? So WHAT does DNA Polymerase do?

12. DNA So, how is DNA copied?

13. DNA Replication What’s the first thing you have to do? Break the H-bonds Helicase does that.

14. AATGGCTAGC

15. DNA Replication It’s almost that simple DNA ‘unzips’ to form a REPLICATION FORK DNA Polymerase puts the bases in (but they have to fit) DNA Polymerase only works 5’ to 3’

18. https://www.youtube.com/watch?v=TNKWgcFPHqw http://www.hhmi.org/biointeractive/dna-replication-advanced-detail https://www.youtube.com/watch?v=JZXT2uOcD2w

19. Review What are the roles of: DNA Polymerase Helicase Ligase Single-Stranded Binding Protein What is the ‘significance’ of the 5 – 3 nature of DNA and DNA Polymerase? Covalent Bond Hydrogen ‘bond’ (interaction)

20. Review In eukaryotes, DNA Polymerase can copy from a few to thousands of bases a SECOND DNA Polymerase has ‘proofreading’ ability How would it ‘know’? Other enzymes can remove just the base later, if needed.

21. Homework “Solve the Chapter Mystery” p. 357 1- 4